help button home button Endocrine Society Endocrinology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Endocrinology, doi:10.1210/en.2007-0597
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Barat, P.
Right arrow Articles by Andrew, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Barat, P.
Right arrow Articles by Andrew, R.
Endocrinology Vol. 148, No. 10 4836-4843
Copyright © 2007 by The Endocrine Society

Effects of Gonadectomy on Glucocorticoid Metabolism in Obese Zucker Rats

Pascal Barat1, Dawn E. W. Livingstone1, Caroline M. C. Elferink, C. Rachel McDonnell, Brian R. Walker and Ruth Andrew

Paediatric Endocrinology (P.B.), Centre Hospitalier Régional Universitaire Bordeaux, Department of Paediatrics, F-33076 Bordeaux, France; and Endocrinology (D.E.W.L., C.M.C.E., C.R.M., B.R.W., R.A.), Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom

Address all correspondence and requests for reprints to: Ruth Andrew, Endocrinology, Centre for Cardiovascular Science, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, United Kingdom. E-mail: Ruth.Andrew{at}ed.ac.uk.


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Glucocorticoids are metabolized by 11ß-hydroxysteroid dehydrogenase 1 (11ßHSD1) and the A-ring reductases (5{alpha}- and 5ß-reductases). Dysregulation of these enzymes has been reported in liver and adipose tissue in obese humans and animals, potentially leading to altered intracellular glucocorticoid concentrations and compensatory activation of the hypothalamic-pituitary-adrenal axis. This dysregulation of glucocorticoid metabolism in obesity is poorly understood. We hypothesized that changes in glucocorticoid metabolism in obesity are mediated by alterations in androgen action. Steroid metabolism was studied in obese and lean male Zucker rats (age 10 wk, 10 animals per group) 4 wk after gonadectomy or sham surgery. Oral glucose tolerance tests were performed, and activities and abundances of mRNAs for steroid metabolizing enzymes were quantified in liver and adipose tissue. Gonadectomy did not consistently alter weight gain, glucose intolerance, or hyperinsulinemia in obese animals. Gonadectomy increased adrenal mass (P < 0.05), suppressed 11ßHSD1 activity and/or mRNA in liver and adipose, increased 5{alpha}-reductase 1 mRNA in liver (P < 0.05), and increased 5ß-reductase activity only in obese animals (P < 0.05). Differences in hepatic 11ßHSD1 mRNA expression and adipose activity between lean and obese animals were normalized by gonadectomy, whereas obese gonadectomized animals maintained elevated liver 5{alpha}-reductase and had an exaggerated elevation of 5ß-reductase activity. We conclude that androgens tonically increase 11ßHSD1 in liver and adipose tissue in male rats and contribute to the dysregulation of 11ßHSD1 in obesity. By contrast, androgens tonically suppress hepatic A-ring reductases in male rats and do not contribute to dysregulation of these enzymes in obesity.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
OBESITY, ESPECIALLY IN a central (or "android") distribution, predisposes to cardiovascular disease and morbidity. Central obesity is a characteristic of glucocorticoid excess, but the role of glucocorticoids in idiopathic obesity has been elusive because obese subjects paradoxically have normal to low circulating plasma concentrations of cortisol (1, 2, 3). Recently, the hypothesis has emerged that intracellular levels of glucocorticoids may be altered in obesity due to dysregulation of glucocorticoid metabolizing enzymes. Tissue concentrations of glucocorticoids are regulated by the activities of 11ß-hydroxysteroid dehydrogenase 1 (11ßHSD1) (4) and the A-ring reductases (5{alpha}- and 5ß-reductases) (5). Changes in the activities and expression of mRNAs of these enzymes have been reported in obese humans (6, 7, 8, 9, 10, 11) and animals (12, 13, 14, 15). In adipose tissue, activation of glucocorticoids by 11ßHSD1 is increased in obesity (8, 9, 10, 11, 16, 17). However, in the liver, activation of glucocorticoids by 11ßHSD1 is decreased (8, 9, 18), and inactivation by A-ring reduction is increased (6, 7). These changes in the liver may reduce local glucocorticoid receptor activation but also increase the metabolic clearance rate of glucocorticoids and thereby induce compensatory activation of the hypothalamic-pituitary-adrenal (HPA) axis.

The mechanisms of dysregulation of glucocorticoid metabolism in obesity are poorly understood but may reflect altered sex steroid action. In the liver, abundances of glucocorticoid metabolizing enzymes are sexually dimorphic and, in some cases, programmed by sex steroids during neonatal life (19, 20, 21). In rats, hepatic 11ßHSD1 is expressed in lower amounts in females than males (22, 23), and in both sexes activity is suppressed, albeit indirectly, by estrogens (23, 24) and stimulated by androgens (25, 26). In cultured hepatocytes, testosterone does not influence the expression of mRNA or activity of 11ßHSD1 (27). However, castration of male rats does suppress hepatic 11ßHSD1 activity toward female levels, although whether this effect is reversed by replacement with testosterone is debated (22, 25). By contrast, in preadipocytes expression of 11ßHSD1 mRNA is stimulated by both androgens and estrogens (28). Conversely, higher circulating androgens in adulthood suppress both hepatic 5{alpha} and 5ß-reduction (20). In humans, 5{alpha}-reduced metabolites of glucocorticoids are more abundant in women compared with men (6). Thus, alterations in liver glucocorticoid metabolism in obesity might reflect reduced androgen action.

The relationship between androgens and obesity is complex and gender specific (29). In prepubertal children (male and female), there is a positive relationship between circulating androgens and indices of obesity (30), and this relationship is maintained in women throughout life. However, in men the positive relationship between androgens and obesity is lost after puberty, and, indeed, obesity is associated with lower testosterone levels (31). This inverse relationship is also observed in some animal models of obesity. Male obese Zucker rats have lower circulating androgens than their lean controls (32), and castration promotes further weight gain (33) but paradoxically improves insulin sensitivity (33, 34). Castration also prevents overt hyperglycemia developing in streptozocin-treated spontaneously hypertensive rats (35) and in mice (36).

We have reported previously that changes in glucocorticoid metabolism observed in human obesity are recapitulated in obese Zucker rats (14, 15, 37). To test the hypotheses that obesity associated changes in glucocorticoid metabolism in obese Zucker rats are mediated by alterations in androgen action and that this might underpin different regulation of glucocorticoid metabolism in liver and adipose tissue, we have investigated steroid metabolism in obese and lean male animals with and without gonadectomy. If impaired androgen action contributes to the derangements in glucocorticoid metabolism observed in obesity, then these changes may normalize in response to gonadectomy.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Solvents were HPLC glass-distilled grade from Rathburn Chemicals (Walkerburn, UK). Other chemicals were from Sigma (Poole, UK) unless otherwise stated.

Animals and procedures
Obese and lean Zucker rats (age 5 wk, young postpubertal males, 10 per group) were obtained from Harlan Olac (Bicester, UK), maintained under controlled conditions of light (on 0800–2000 h) and temperature (21 C), and allowed free access to standard rat chow (Special Diet Services, Witham, UK) and drinking water. All animal experiments were performed in accordance with accepted standards of humane animal care, under United Kingdom Home Office license. Surgery, either bilateral gonadectomy or sham surgery, was performed on 6-wk-old rats under 4% halothane anesthesia. All rats were then weighed every third day. After 3 wk, animals underwent an oral glucose tolerance test, as described previously (37). At 10 wk of age, 4 wk after surgery, rats were fasted overnight and decapitated at 0900–1100 h. Trunk blood was collected, and tissues were dissected and snap frozen on dry ice.

Plasma assays
High-density lipoprotein (HDL)-cholesterol, total cholesterol, and triglycerides were measured in plasma by enzymatic colorimetric techniques using a Vitros 5,1 analyzer (Johnson & Johnson, New Brunswick, NJ). Glucose and insulin were measured by a hexokinase assay (Sigma) and ELISA (Crystal Chem, Inc., Chicago, IL), respectively. Plasma corticosterone was measured by in-house RIA (38), modified for the microtiter plate scintillation proximity assay. Testosterone and ACTH were measured by ELISA (DRG Instruments Gmbh, Germany, and Crystal Chem, Inc., respectively).

Quantification of mRNAs by real-time PCR
For quantitative comparisons between groups, total RNA was extracted from snap-frozen tissue using Trizol reagent (Life Technologies, Inc., Paisley, UK). For adipose tissue, RNA was purified using RNAid RNA binding matrix (Anachem, Luton, UK). RNA was quantified using a fluorometric assay (Ribogreen; Invitrogen Ltd., Paisley, UK) and integrity assessed by electrophoresis on agarose gel. Random-primed cDNA was synthesized from RNA (0.5 µg) using the Promega Reverse Transcription System (Promega UK, Southampton, UK). Quantification of transcript was performed with real-time PCR primer-probe sets using the ABI PRISM 7700/7900 Sequence Detection System with the following primers and probes [forward (F), reverse (R)]: 11ßHSD1: 5'-CATAGACACAGAAACAGCTTTGAAA-3' (forward), 5'-CTCCAGGGCGCATTCCT-3' (reverse), and 5'-6-FAMCTGGGATAATCTTGAGTCAAGCTGCTCCC-TAMRA3'(probe)

5{alpha}-Reductase type 1: 5'-CTGTTTCCTGACAGGCTTTGC-3' (forward), 5'-GCCTCCCCTGGGTATCTTGT-3' (reverse), and 5'-6-FAM-CAGACCACATCCTGAGGAATCTGAGAAAACC-TAMRA-3' (probe)

5ß-Reductase: 5'-GCCTTTAAGCCTGGAGAGGAA-3' (forward), 5'-ACGTGGCACACAGATTTGATT-3' (reverse), and 5'-6-FAM-TGGTATATCACTCGGCCATTCTATCTTTAGGAT-TAMRA-3' (probe)

3{alpha}-HSD: 5'-TCTATACTTCAAAGCTTTGGAGCACTT-3' (forward), 5'-CCAGTTGAGTGCTTTTCAGTGTCT-3' (reverse), and 5'-6-FAM-TCCAAGCAAGTTCGGACCAGATCTG-TAMRA-3' (probe)

Cyclophilin: 5'-CCCACCGTGTTCTTCGACAT-3' (forward), 5'-GAAAGTTTTCTGCTGTCTTTGGAACT-3' (reverse), and 5'-6-FAM-CAAGGGCTCGCCATCAGCCGT-TAMRA-3' (probe)

A standard curve for each primer probe set was generated by serial dilution of cDNA pooled from several animals. Each sample was run in duplicate, and the mean values of the duplicates were used to calculate transcript level from the standard curve of the same tissue. Cyclophilin and 18S (Applied Biosystems, Cheshire, UK) were used to normalize transcript levels. In the liver the abundances of their mRNAs did not differ between treatments or genotypes, and, therefore, the mean of their results was used for correction. However, 18S alone was used to correct results from omental and sc fat because the abundance of transcript for cyclophilin differed between groups. RT-negative controls and intron-spanning primers were used to examine for and prevent amplification of genomic DNA.

Measurement of enzyme activities
The conversion of 1,2,6,7-[3H]4-corticosterone (GE Healthcare, Buckinghamshire, UK) to [3H]4-11-dehydrocorticosterone by 11ßHSD1 in hepatic microsomes (15 µg/ml protein) or adipose homogenate (100 µg/ml protein) was determined as described previously (14). 5ß-Reductase activity in the liver was assessed by the conversion of [3H]4-corticosterone to [3H]4-5ß-tetrahydrocorticosterone in hepatic cytosol as described previously (15).

The activity of 5{alpha}-reductase 1 could not be determined due to the instability of hepatic protein, as reported by Eicheler et al. (39). The activity of 3{alpha}HSD was not measured because it is not rate determining.

Statistics
All data are expressed as mean ± SEM; there were 10 animals in all groups. Data were analyzed by repeated measure and two-way ANOVA to test for effects of obesity and gonadectomy and the interaction between them, followed by post hoc Fisher’s least squares difference tests, as appropriate.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Body and tissue weights
Among sham-operated animals, obese rats were heavier at baseline, gained more weight during the experiment (Fig. 1Go), and had heavier thymus glands and lighter prostate glands (Table 1Go). With the exception of prostate weight, these differences persisted among gonadectomized rats. Gonadectomy dramatically reduced prostate gland weight and increased adrenal weight in both lean and obese animals, and increased thymus weight in lean animals only.


Figure 1
View larger version (12K):
[in this window]
[in a new window]

  		FIG. 1. Body weight changes. Data are mean ± SEM. Open shapes designate sham rats, filled shapes gonadectomy (GDX) rats, squares lean rats, and circles obese rats. There were significant effects of obesity (P < 0.001) but not of gonadectomy and no significant interaction.

 

View this table:
[in this window]
[in a new window]

  		TABLE 1. Comparisons of metabolic characteristics in lean, obese, nongonadectomized, and gonadectomized (GDX) Zucker rats

 
Biochemical measures
Among sham-operated animals, obese rats had elevated plasma glucose and insulin concentrations during the glucose tolerance test (Fig. 2Go), and higher cholesterol, HDL-cholesterol, and triglyceride levels in plasma (Table 1Go). Gonadectomy lowered circulating testosterone, and increased basal glucose levels in both lean and obese rats during the glucose tolerance test but did not alter insulin concentrations (Fig. 2Go). Circulating corticosterone was not altered either by obesity or gonadectomy, however, ACTH levels were higher in the obese rats.


Figure 2
View larger version (12K):
[in this window]
[in a new window]

  		FIG. 2. Oral glucose tolerance tests. Data are mean ± SEM for plasma glucose (A) and insulin (B) levels 0, 30, and 120 min after oral glucose bolus. Open shapes designate sham rats, filled shapes gonadectomy (GDX) rats, squares lean rats, and circles obese rats. P values for repeated measure two-way ANOVA for the effect of obesity and gonadectomy and the interaction between them are shown in boxed text. Obese rats had higher concentrations of glucose and insulin than their lean counterparts. Gonadectomy significantly increased glucose, but not insulin. Ns, Nonsignificant.

 
Hepatic enzymes: activities and abundance of transcripts (Fig. 3Go)
Obese rats had lower 11ßHSD1 activities (significant post hoc in gonadectomized animals only) and mRNA. They had higher 5ß-reductase activity, without a difference in 5ß-reductase mRNA, and a higher abundance of mRNA for 5{alpha}-reductase 1 (when compared overall but not significant post hoc) but not for 3{alpha}HSD. Gonadectomy reduced 11ßHSD1 activity and mRNA expression, increased the abundance of 5{alpha}-reductase 1 and 3{alpha}HSD mRNAs, but exaggerated the increase in 5ß-reductase activity in obese rats (P < 0.05 vs. obese sham).


Figure 3
View larger version (21K):
[in this window]
[in a new window]

  		FIG. 3. Hepatic enzyme activity and abundance of mRNA transcripts. Data are mean ± SEM. A, 11ßHSD1 activity. B, 11ßHSD1 mRNA. C, 5ß-Reductase activity. D, 5ß-Reductase mRNA. E, 5{alpha}-Reductase 1 mRNA. F, 3{alpha}HSD mRNA. Sham animals are shown as open bars and gonadectomy (GDX) animals as filled bars. P values shown in boxed text are for two-way ANOVA for the effect of obesity and gonadectomy and the interaction between them. *, P < 0.05; **, P < 0.01; ***, P < 0.001), followed by post hoc Fisher’s tests as brackets. Ns, Nonsignificant.

 
Adipose enzymes: activities and abundance of transcripts
Omental adipose tissue (Fig. 4Go).
Obese sham rats had higher expression of mRNAs for 5{alpha}-reductase 1 and 11ßHSD1, but this was not matched by increased 11ßHSD1 enzyme activity. Gonadectomy suppressed expression of 11ßHSD1 mRNA but only decreased activity in lean animals. Gonadectomy normalized 5{alpha}-reductase type 1 mRNA in obese rats (P < 0.05), and decreased 3{alpha}HSD mRNA expression in lean and obese rats.


Figure 4
View larger version (19K):
[in this window]
[in a new window]

  		FIG. 4. Omental adipose tissue enzyme activity and the abundance of mRNA transcripts. Data are mean ± SEM. A, 11ßHSD1 activity. B, 11ßHSD1 mRNA. C, 5{alpha}-Reductase 1 mRNA. D, 3{alpha}HSD mRNA. Sham animals are shown as open bars and gonadectomy (GDX) animals as filled bars. P values shown in boxed text are for two-way ANOVA for the effect of obesity and gonadectomy and the interaction between them. *, P < 0.05; **, P < 0.01; ***, P < 0.001, followed by post hoc Fisher’s test as brackets. Ns, Nonsignificant.

 
Subcutaneous adipose tissue (Fig. 5Go).
The activity of 11ßHSD1 (P < 0.001), but not transcript abundance, was lower in obese sham compared with lean sham animals, and this difference was abolished by gonadectomy, which reduced 11ßHSD1 activity, more so in lean animals (P < 0.05). There was no influence of obesity or gonadectomy on 5{alpha}-reductase 1 mRNA expression, but gonadectomy reduced 3{alpha}HSD mRNA abundance only in obese animals (P < 0.05).


Figure 5
View larger version (19K):
[in this window]
[in a new window]

  		FIG. 5. Subcutaneous adipose tissue enzyme activity and the abundance of mRNA transcripts. Data are mean ± SEM. A, 11ßHSD1 activity. B, 11ßHSD1 mRNA. C, 5{alpha}-Reductase 1 mRNA. D, 3{alpha}HSD mRNA. Sham animals are shown as open bars and gonadectomy (GDX) animals as filled bars. P values shown in boxed text are for two-way ANOVA for the effect of obesity and gonadectomy and the interaction between them. *, P < 0.05; **, P < 0.01; ***, P < 0.001), followed by post hoc Fisher’s test as brackets. Ns, Nonsignificant.

 

   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
The changes in glucocorticoid metabolism observed in human obesity are recapitulated in the obese Zucker rat, namely increased hepatic A-ring reduction and tissue-specific changes in the activity of 11ßHSD1 (14, 15, 37). Previous studies have shown that the obese phenotype in these rats is dependent on glucocorticoids, and, indeed, adrenalectomy normalizes features such as weight gain, insulin resistance, hypertension, and dyslipidemia, along with changes in expression of mRNA and/or the activity of hepatic 11ßHSD1 and A-ring reductases (37). Reversal of insulin resistance alone ameliorates the overexpression of hepatic 5{alpha}-reductase 1 mRNA but does not normalize the alterations in the activity of 11ßHSD1 or of 5ß-reductase, suggesting a further contributory factor (15, 37). This study demonstrates that androgens also have a profound influence on glucocorticoid metabolism and that some, but not all, of the changes associated with obesity may be related to impaired androgen action in this condition.

Obesity in adult men is associated with low androgen levels in the blood (31), but this may be explained in part by low sex hormone binding globulin levels (31), so that the extent to which free androgens are reduced at the target tissue is debated. Male Zucker rats are reported to have low circulating androgens (32), although in our study this was a nonsignificant trend. However, our finding of low prostate weight supports the notion of functional androgen deficiency in the obese rats. Surprisingly, however, castration of rats reportedly causes an exaggerated gain in weight (33) and subtly improved insulin sensitivity (15, 37). Our data do not confirm these effects of castration on body weight but demonstrate a small increase in plasma glucose after gonadectomy. In the studies reported previously, the animals were studied after longer periods of gonadectomy or with castration at an earlier age (33), perhaps exaggerating the small effects.

The effects of gonadectomy on glucocorticoid metabolism were tissue specific, and also differed between lean and obese animals. The basal hepatic activity of 11ßHSD1 was decreased, and the abundance of transcript of 5{alpha}-reductase 1 and 3{alpha}-HSDs increased by gonadectomy. However, the magnitude of these changes was similar, and so the baseline difference between lean and obese animals remained, implying the changes observed in obesity are independent of androgen action. In contrast, the difference in expression of 11ßHSD1 mRNA between lean and obese animals was normalized, and the increase in 5ß-reductase mRNA in the liver of obese animals was exaggerated after gonadectomy, suggesting a role for androgens in the dysregulation of these enzymes in obesity. In omental and sc adipose tissue, the activity and mRNA expression of 11ßHSD1 were also tonically stimulated by androgens. The differences in adipose activity associated with obesity were obviated by gonadectomy, which also normalized the overexpression of 5{alpha}-reductase 1 mRNA in omental adipose and 3{alpha}HSD in sc adipose. This complex interplay between androgen and glucocorticoid action may mediate some of the variable effects of androgens on fat distribution and fuel partitioning.

These data support a role for androgens in stimulating baseline expression of 11ßHSD1 mRNA in both the liver and adipose. Broadly, the differences in expression of hepatic 11ßHSD1 mRNA and adipose activity in obesity were normalized by gonadectomy. It is possible that a reduction in liver 11ßHSD1 activity due to androgen deficiency may mediate beneficial long-term metabolic effects (40). Indeed, global 11ßHSD1 deficiency or inhibition in mice is associated with enhanced liver insulin sensitivity and protection against features of the metabolic syndrome on high fat feeding (41, 42, 43, 44). Discrepancies between the abundance of mRNA and protein reported here for 11ßHSD1 in omental adipose are as yet unexplained, although posttranslational modifications may contribute (45). Bujalska (46) and Jang (47) et al. also reported a lack of correlation between transcript and activity in pre-adipocytes and muscle, respectively. Tissue-specific competitive inhibitors against 11ßHSD1 (e.g. hepatic bile acids) (48) may be altered by interventions explaining these effects.

However, although impaired androgen action in obesity may explain the down-regulation of hepatic 11ßHSD1 in obesity, this is clearly not the explanation of increased adipose 11ßHSD1 observed in obesity (8, 9, 11). Indeed, in contrast, suppression of 11ßHSD1 was evident in adipose after gonadectomy of lean animals, an observation supported by dihydrotestosterone inducing transcription of 11ßHSD1 in pre-adipocytes (28). In adipose, unlike the liver, androgens may be converted to estrogens by aromatase that is up-regulated in obesity (49), perhaps limiting the effects of intact androgens in this tissue in the obese state (28).

Effects of androgen deficiency to increase A-ring reduction might also, in principle, alter glucocorticoid action within the liver, but there is as yet little evidence (50) that the activity of these enzymes influences local glucocorticoid receptor activation. It is more likely that the major consequence of increased A-ring reductase activity is an increase in metabolic clearance of glucocorticoids, which is compensated for by activation of the HPA axis, consistent with the observed enlargement of the adrenal glands. Indeed, previous studies have documented interactions between androgen levels and the HPA axis (51, 52). However, the increase in adrenal size in response to gonadectomy may also be explained by the ability of testosterone to repress expression of the corticotrophin-releasing factor (53). Thorough testing of the stress axis was not performed here, and measures of the HPA axis were only possible under partially stressed conditions at cull and, thus, did not reflect truly basal conditions. Plasma ACTH was increased in obesity, but not by gonadectomy, with maintenance of normal circulating corticosterone. In obesity, ACTH may be more responsive to the acute stress of sampling, resulting from activation of the HPA axis, either centrally or peripherally.

Hepatic A-ring reductases are under tonic suppression by androgens (20). El-Awady et al. (54) showed that removal of sex steroids in healthy male rats resulted in overexpression of hepatic 5{alpha}-reductase 1 mRNA, perhaps by posttranscriptional stabilization of mRNA. However, again there are likely to be additional signals that operate in obesity, e.g. acting in conjunction with IGF-I to up-regulate 5{alpha}-reductase 1 (55). Interaction between impaired androgenic actions and insulin resistance per se may explain altered expression of 5{alpha}-reductase 1 transcript, in keeping with our previous reports of the reversal of up-regulation of 5{alpha}-reductase 1 expression after insulin sensitization (15). In contrast, because castration enhanced expression and activity of 5ß-reductase in obese but not lean rats, this may explain why insulin sensitization alone does not fully reverse the overexpression of this enzyme in obesity. Discrepancies were apparent between the abundance of gene product and activity of 5ß-reductase in lean rats, and this may be due to motifs in the 3' UTR of mRNA encoding 5ß-reductase targeting it for prompt degradation (56, 57).

In conclusion, androgens play a powerful role in regulating the panel of enzymes involved with hepatic and adipose metabolism of glucocorticoids, and androgen deficiency may contribute to variations in glucocorticoid metabolism in obesity in leptin-resistant Zucker rats, most notably by enhancing the rate of steroid metabolism by 5ß-reductase and 11ßHSD1. The potential role of androgen deficiency in explaining alterations in hepatic cortisol metabolism in human obesity (6, 8, 9, 18), and its effects upon HPA axis activation in obesity, is now worthy of attention.


   Acknowledgments
 
We thank Scott Denham and Alison Ayres for excellent technical assistance.


   Footnotes
 
This work was supported by the British Heart Foundation, the Wellcome Trust, the Société Française d’Endocrinologie, and the Fond pour la Recherche Médicale.

Disclosure Statement: The authors have nothing to declare.

First Published Online July 12, 2007

1 P.B. and D.E.W.L. are joint first authors and contributed equally to the experiments and manuscript. Back

Abbreviations: HDL, High-density lipoprotein; HPA, hypothalamic-pituitary-adrenal; 11ßHSD1, 11ß-hydroxysteroid dehydrogenase 1.

Received May 4, 2007.

Accepted for publication June 28, 2007.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Phillips DI, Barker DJ, Fall CH, Seckl JR, Whorwood CB, Wood PJ, Walker BR 1998 Elevated plasma cortisol concentrations: a link between low birth weight and the insulin resistance syndrome? J Clin Endocrinol Metab 83:757–760[Abstract/Free Full Text]
  2. Rosmond R, Dallman MF, Bjorntorp P 1998 Stress-related cortisol secretion in men: relationships with abdominal obesity and endocrine, metabolic and hemodynamic abnormalities. J Clin Endocrinol Metab 83:1853–1859[Abstract/Free Full Text]
  3. Filipovsky J, Ducimetiere P, Eschwege E, Richard JL, Rosselin G, Claude JR 1996 The relationship of blood pressure with glucose, insulin, heart rate, free fatty acids and plasma cortisol levels according to degree of obesity in middle-aged men. J Hypertens 14:229–235[CrossRef][Medline]
  4. Seckl JR, Walker BR 2004 11ß-Hydroxysteroid dehydrogenase type 1 as a modulator of glucocorticoid action: from metabolism to memory. Trends Endocrinol Metab 15:418–424[CrossRef][Medline]
  5. Andrew R, Walker BR 2002 Glucocorticoid metabolism in health and disease. In: Recent research developments in endocrinology. Vol. 3. Trivandrum, India: Transworld Research Network; 425–449
  6. Andrew R, Phillips DI, Walker BR 1998 Obesity and gender influence cortisol secretion and metabolism in man. J Clin Endocrinol Metab 83:1806–1809[Abstract/Free Full Text]
  7. Fraser R, Ingram MC, Anderson NH, Morrison C, Davies E, Connell JM 1999 Cortisol effects on body mass, blood pressure, and cholesterol in the general population. Hypertension 33:1364–1368[Abstract/Free Full Text]
  8. Rask E, Olsson T, Soderberg S, Andrew R, Livingstone DE, Johnson O, Walker BR 2001 Tissue-specific dysregulation of cortisol metabolism in human obesity. J Clin Endocrinol Metab 86:1418–1421[Abstract/Free Full Text]
  9. Rask E, Walker BR, Soderberg S, Livingstone DE, Eliasson M, Johnson O, Andrew R, Olsson T 2002 Tissue-specific changes in peripheral cortisol metabolism in obese women: increased adipose 11ß-hydroxysteroid dehydrogenase type 1 activity. J Clin Endocrinol Metab 87:3330–3336[Abstract/Free Full Text]
  10. Lindsay RS, Wake DJ, Nair S, Bunt J, Livingstone DE, Permana PA, Tataranni PA, Walker BR 2003 Subcutaneous adipose 11 ß-hydroxysteroid dehydrogenase type 1 activity and messenger ribonucleic acid levels are associated with adiposity and insulinemia in Pima Indians and Caucasians. J Clin Endocrinol Metab 88:2738–2744[Abstract/Free Full Text]
  11. Wake DJ, Rask E, Livingstone DE, Soderberg S, Olsson T, Walker BR 2003 Local and systemic impact of transcriptional up-regulation of 11ß-hydroxysteroid dehydrogenase type 1 in adipose tissue in human obesity. J Clin Endocrinol Metab 88:3983–3988[Abstract/Free Full Text]
  12. Aoki K, Homma M, Hirano T, Oka K, Satoh S, Mukasa K, Ito S, Sekihara H 2001 MRNA and enzyme activity of hepatic 11ß-hydroxysteroid dehydrogenase type 1 are elevated in C57BL/KsJ-db/db mice. Life Sci 69:2543–2549[CrossRef][Medline]
  13. Liu Y, Nakagawa Y, Wang Y, Li R, Li X, Ohzeki T, Friedman TC 2003 Leptin activation of corticosterone production in hepatocytes may contribute to the reversal of obesity and hyperglycemia in leptin-deficient ob/ob mice. Diabetes 52:1409–1416[Abstract/Free Full Text]
  14. Livingstone DE, Jones GC, Smith K, Jamieson PM, Andrew R, Kenyon CJ, Walker BR 2000 Understanding the role of glucocorticoids in obesity: tissue-specific alterations of corticosterone metabolism in obese Zucker rats. Endocrinology 141:560–563[Abstract/Free Full Text]
  15. Livingstone DE, McInnes KJ, Walker BR, Andrew R 2005 Increased A-ring reduction of glucocorticoids in obese Zucker rats: effects of insulin sensitization. Obes Res 13:1523–1526[Medline]
  16. Paulmyer-Lacroix O, Boullu S, Oliver C, Alessi MC, Grino M 2002 Expression of the mRNA coding for 11ß-hydroxysteroid dehydrogenase type 1 in adipose tissue from obese patients: an in situ hybridization study. J Clin Endocrinol Metab 87:2701–2705[Abstract/Free Full Text]
  17. Engeli S, Bohnke J, Feldpausch M, Gorzelniak K, Heintze U, Janke J, Luft FC, Sharma AM 2004 Regulation of 11ß-HSD genes in human adipose tissue: influence of central obesity and weight loss. Obes Res 12:9–17[Medline]
  18. Stewart PM, Boulton A, Kumar S, Clark PM, Shackleton CH 1999 Cortisol metabolism in human obesity: impaired cortisone–>cortisol conversion in subjects with central adiposity. J Clin Endocrinol Metab 84:1022–1027[Abstract/Free Full Text]
  19. Einarsson K, Gustafsson JA, Stenberg A 1973 Neonatal imprinting of liver microsomal hydroxylation and reduction of steroids. J Biol Chem 248:4987–4997[Abstract/Free Full Text]
  20. Gustafsson JA, Stenberg A 1974 Irreversible androgenic programming at birth of microsomal and soluble rat liver enzymes active on androstene-3,17-dione and 5{alpha}-androstane-3{alpha},17ß-diol. J Biol Chem 249:711–718[Abstract/Free Full Text]
  21. Jansson JO, Ekberg S, Isaksson O, Mode A, Gustafsson JA 1985 Imprinting of growth hormone secretion, body growth, and hepatic steroid metabolism by neonatal testosterone. Endocrinology 117:1881–1889[Abstract/Free Full Text]
  22. Lax ER, Ghraf R, Schriefers H 1978 The hormonal regulation of hepatic microsomal 11beta-hydroxysteroid dehydrogenase activity in the rat. Acta Endocrinol (Copenh) 89:352–358[Abstract/Free Full Text]
  23. Low SC, Chapman KE, Edwards CR, Wells T, Robinson IC, Seckl JR 1994 Sexual dimorphism of hepatic 11ß-hydroxysteroid dehydrogenase in the rat: the role of growth hormone patterns. J Endocrinol 143:541–548[Abstract/Free Full Text]
  24. Jamieson PM, Nyirenda MJ, Walker BR, Chapman KE, Seckl JR 1999 Interactions between oestradiol and glucocorticoid regulatory effects on liver-specific glucocorticoid-inducible genes: possible evidence for a role of hepatic 11beta-hydroxysteroid dehydrogenase type 1. J Endocrinol 160:103–109[Abstract]
  25. Low SC, Assaad SN, Rajan V, Chapman KE, Edwards CR, Seckl JR 1993 Regulation of 11ß-hydroxysteroid dehydrogenase by sex steroids in vivo: further evidence for the existence of a second dehydrogenase in rat kidney. J Endocrinol 139:27–35[Abstract/Free Full Text]
  26. Liu YJ, Nakagawa Y, Toya K, Ozeki T 1997 Sex-specific effects of growth hormone on hepatic 11ß-hydroxysteroid dehydrogenase activity and gene expression in hypothyroid rats. Life Sci 61:325–334[CrossRef][Medline]
  27. Nwe KH, Hamid A, Morat PB, Khalid BA 2000 Differential regulation of the oxidative 11ß-hydroxysteroid dehydrogenase activity in testis and liver. Steroids 65:40–45[CrossRef][Medline]
  28. Dieudonne MN, Sammari A, Dos SE, Leneveu MC, Giudicelli Y, Pecquery R 2006 Sex steroids and leptin regulate 11ß-hydroxysteroid dehydrogenase I and P450 aromatase expressions in human preadipocytes: sex specificities. J Steroid Biochem Mol Biol 99:189–196[CrossRef][Medline]
  29. Pasquali R 2006 Obesity and androgens: facts and perspectives. Fertil Steril 85:1319–1340[CrossRef][Medline]
  30. Reinehr T, de Sousa G, Roth CL, Andler W 2005 Androgens before and after weight loss in obese children. J Clin Endocrinol Metab 90:5588–5595[Abstract/Free Full Text]
  31. Zumoff B, Strain GW, Miller LK, Rosner W, Senie R, Seres DS, Rosenfeld RS 1990 Plasma free and non-sex-hormone-binding-globulin-bound testosterone are decreased in obese men in proportion to their degree of obesity. J Clin Endocrinol Metab 71:929–931[Abstract/Free Full Text]
  32. Whitaker EM, Shaw MA, Hervey GR 1983 Plasma oestradiol-17ß and testosterone concentrations as possible causes of the infertility of congenitally obese Zucker rats. J Endocrinol 99:485–490[Abstract/Free Full Text]
  33. Ajayi AA, Ogungbade GO, Okorodudu AO 2004 Sex hormone regulation of systemic endothelial and renal microvascular reactivity in type-2 diabetes: studies in gonadectomized and sham-operated Zucker diabetic rats. Eur J Clin Invest 34:349–357[CrossRef][Medline]
  34. Kava RA, West DB, Lukasik VA, Wypijewski C, Wojnar Z, Johnson PR, Greenwood MR 1992 The effects of gonadectomy on glucose tolerance of genetically obese (fa/fa) rats: influence of sex and genetic background. Int J Obes Relat Metab Disord 16:103–111[Medline]
  35. Iwase M, Wakisaka M, Yoshinari M, Sato Y, Yoshizumi H, Nunoi K, Fujishima M 1996 Effect of gonadectomy on the development of diabetes mellitus, hypertension, and albuminuria in the rat model. Metabolism 45:155–161[CrossRef][Medline]
  36. Maclaren NK, Neufeld M, McLaughlin JV, Taylor G 1980 Androgen sensitization of streptozotocin-induced diabetes in mice. Diabetes 29:710–716[Medline]
  37. Livingstone DE, Kenyon CJ, Walker BR 2000 Mechanisms of dysregulation of 11 beta-hydroxysteroid dehydrogenase type 1 in obese Zucker rats. J Endocrinol 167:533–539[Abstract]
  38. Holmes MC, French KL, Seckl JR 1997 Dysregulation of diurnal rhythms of serotonin 5-HT2C and corticosteroid receptor gene expression in the hippocampus with food restriction and glucocorticoids. J Neurosci 17:4056–4065[Abstract/Free Full Text]
  39. Eicheler W, Seitz J, Steinhoff M, Forssmann WG, Adermann K, Aumuller G 1995 Distribution of rat hepatic steroid 5 alpha-reductase 1 as shown by immunohistochemistry. Exp Clin Endocrinol Diabetes 103:105–112[Medline]
  40. Paterson JM, Morton NM, Fievet C, Kenyon CJ, Holmes MC, Staels B, Seckl JR, Mullins JJ 2004 Metabolic syndrome without obesity: hepatic overexpression of 11beta-hydroxysteroid dehydrogenase type 1 in transgenic mice. Proc Natl Acad Sci USA 101:7088–7093[Abstract/Free Full Text]
  41. Morton NM, Holmes MC, Fievet C, Staels B, Tailleux A, Mullins JJ, Seckl JR 2001 Improved lipid and lipoprotein profile, hepatic insulin sensitivity, and glucose tolerance in 11beta-hydroxysteroid dehydrogenase type 1 null mice. J Biol Chem 276:41293–41300[Abstract/Free Full Text]
  42. Alberts P, Nilsson C, Selen G, Engblom LO, Edling NH, Norling S, Klingstrom G, Larsson C, Forsgren M, Ashkzari M, Nilsson CE, Fiedler M, Bergqvist E, Ohman B, Bjorkstrand E, Abrahmsen LB 2003 Selective inhibition of 11 ß-hydroxysteroid dehydrogenase type 1 improves hepatic insulin sensitivity in hyperglycemic mice strains. Endocrinology 144:4755–4762[CrossRef][Medline]
  43. Alberts P, Engblom L, Edling N, Forsgren M, Klingstrom G, Larsson C, Ronquist-Nii Y, Ohman B, Abrahmsen L 2002 Selective inhibition of 11beta-hydroxysteroid dehydrogenase type 1 decreases blood glucose concentrations in hyperglycaemic mice. Diabetologia 45:1528–1532[CrossRef][Medline]
  44. Hermanowski-Vosatka A, Balkovec JM, Cheng K, Chen HY, Hernandez M, Koo GC, Le Grand CB, Li Z, Metzger JM, Mundt SS, Noonan H, Nunes CN, Olson SH, Pikounis B, Ren N, Robertson N, Schaeffer JM, Shah K, Springer MS, Strack AM, Strowski M, Wu K, Wu T, Xiao J, Zhang BB, Wright SD, Thieringer R 2005 11ß-HSD1 inhibition ameliorates metabolic syndrome and prevents progression of atherosclerosis in mice. J Exp Med 202:517–527[Abstract/Free Full Text]
  45. Oppermann UC, Netter KJ, Maser E 1995 Cloning and primary structure of murine 11ß-hydroxysteroid dehydrogenase/microsomal carbonyl reductase. Eur J Biochem 227:202–208[Medline]
  46. Bujalska IJ, Draper N, Michailidou Z, Tomlinson JW, White PC, Chapman KE, Walker EA, Stewart PM 2005 Hexose-6-phosphate dehydrogenase confers oxo-reductase activity upon 11ß-hydroxysteroid dehydrogenase type 1. J Mol Endocrinol 34:675–684[Abstract/Free Full Text]
  47. Jang C, Obeyesekere VR, Dilley RJ, Alford FP, Inder WJ 2006 11Beta hydroxysteroid dehydrogenase type 1 is expressed and is biologically active in human skeletal muscle. Clin Endocrinol (Oxf) 65:800–805[CrossRef][Medline]
  48. Morris DJ, Souness GW, Latif SA, Hardy MP, Brem AS 2004 Effect of chenodeoxycholic acid on 11ß-hydroxysteroid dehydrogenase in various target tissues. Metabolism 53:811–816[CrossRef][Medline]
  49. Wake DJ, Strand M, Rask E, Westerbacka J, Livingstone DE, Soderberg S, Andrew R, Yki-Jarvinen H, Olsson T, Walker BR 2007 Intra-adipose sex steroid metabolism and body fat distribution in idiopathic human obesity. Clin Endocrinol (Oxf) 66:440–446[CrossRef][Medline]
  50. McInnes KJ, Kenyon CJ, Chapman KE, Livingstone DE, Macdonald LJ, Walker BR, Andrew R 2004 5{alpha}-Reduced glucocorticoids, novel endogenous activators of the glucocorticoid receptor. J Biol Chem 279:22908–22912[Abstract/Free Full Text]
  51. Kirschbaum C, Kudielka BM, Gaab J, Schommer NC, Hellhammer DH 1999 Impact of gender, menstrual cycle phase, and oral contraceptives on the activity of the hypothalamus-pituitary-adrenal axis. Psychosom Med 61:154–162[Abstract/Free Full Text]
  52. Rubinow DR, Roca CA, Schmidt PJ, Danaceau MA, Putnam K, Cizza G, Chrousos G, Nieman L 2005 Testosterone suppression of CRH-stimulated cortisol in men. Neuropsychopharmacology 30:1906–1912[CrossRef][Medline]
  53. Bao AM, Fischer DF, Wu YH, Hol EM, Balesar R, Unmehopa UA, Zhou JN, Swaab DF 2006 A direct androgenic involvement in the expression of human corticotropin-releasing hormone. Mol Psychiatry 11:567–576[CrossRef][Medline]
  54. El-Awady MK, El Garf W, El Houssieny L 2004 Steroid 5{alpha} reductase mRNA type 1 is differentially regulated by androgens and glucocorticoids in the rat liver. Endocr J 51:37–46[CrossRef][Medline]
  55. Horton R, Pasupuletti V, Antonipillai I 1993 Androgen induction of steroid 5 {alpha}-reductase may be mediated via insulin-like growth factor-I. Endocrinology 133:447–451[Abstract/Free Full Text]
  56. Kondo KH, Kai MH, Setoguchi Y, Eggertsen G, Sjoblom P, Setoguchi T, Okuda KI, Bjorkhem I 1994 Cloning and expression of cDNA of human {Delta} 4-3-oxosteroid 5ß-reductase and substrate specificity of the expressed enzyme. Eur J Biochem 219:357–363[Medline]
  57. Onishi Y, Noshiro M, Shimosato T, Okuda K 1991 Molecular cloning and sequence analysis of cDNA encoding {Delta} 4-3-ketosteroid 5ß-reductase of rat liver. FEBS Lett 283:215–218[CrossRef][Medline]



This article has been cited by other articles:


Home page
 J EndocrinolHome page
D. E W Livingstone, S. L Grassick, G. L Currie, B. R Walker, and R. Andrew
Dysregulation of glucocorticoid metabolism in murine obesity: comparable effects of leptin resistance and deficiency
J. Endocrinol., May 1, 2009; 201(2): 211 - 218.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Barat, P.
Right arrow Articles by Andrew, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Barat, P.
Right arrow Articles by Andrew, R.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Endocrinology Endocrine Reviews J. Clin. End. & Metab.
Molecular Endocrinology Recent Prog. Horm. Res. All Endocrine Journals