Endocrinology, Vol 125, 2434-2438, Copyright © 1989 by Endocrine Society

ARTICLES

The effect of a 5 alpha-reductase inhibitor on androgen physiology in the immature male rat

FW George, L Johnson and JD Wilson
Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas 75235.

To provide insight into the role of 5 alpha-dihydrotestosterone (DHT) in postnatal androgen physiology, we administered the 5 alpha-reductase inhibitor finasteride to male rats from birth through the onset of puberty. In 4-week-old control rats serum testosterone levels averaged 0.21 ng/ml, and DHT levels averaged 0.64 ng/ml. By 7 weeks of age, testosterone levels increased more than 7-fold to 1.57 ng/ml, while the circulating DHT level declined to 0.26 ng/ml. In both the 4- and 7-week- old inhibitor-treated animals, circulating DHT levels were 25-50% of control values, and circulating testosterone levels were higher than control values. In 7-week-old inhibitor-treated rats, the weights of prostate, penis, seminal vesicles, and epididymal tissues were only 30- 50% those of the controls. However, DHT formation is apparently not critical for postnatal development of the preputial glands or the androgen-dependent perineal muscles, since the weights of these tissues were not affected by treatment with inhibitor. Treatment with the 5 alpha-reductase inhibitor had no apparent effect on testicular histology or daily sperm production despite the fact that testicular DHT content was lower (70%) and testosterone content was higher (250%) than those in controls. We conclude that DHT formation is important for the normal postnatal growth of the prostate, seminal vesicles, epididymis, and penis and may be important for normal feedback control of testosterone production in rats, but that its formation is not critical for the onset of spermatogenesis or the development of the preputial glands or the androgen-dependent perineal muscles.

This article has been cited by other articles:

				C. R. Blystone, J. Furr, C. S. Lambright, K. L. Howdeshell, B. C. Ryan, V. S. Wilson, G. A. LeBlanc, and L. E. Gray Jr Prochloraz Inhibits Testosterone Production at Dosages below Those that Affect Androgen-Dependent Organ Weights or the Onset of Puberty in the Male Sprague Dawley Rat Toxicol. Sci., May 1, 2007; 97(1): 65 - 74. [Abstract] [Full Text] [PDF]

				N. A. Henderson and B. Robaire Effects of PNU157706, a Dual 5{alpha}-Reductase Inhibitor, on Rat Epididymal Sperm Maturation and Fertility Biol Reprod, February 1, 2005; 72(2): 436 - 443. [Abstract] [Full Text] [PDF]

				C. J. Bowman, N. J. Barlow, K. J. Turner, D. G. Wallace, and P. M. D. Foster Effects of in Utero Exposure to Finasteride on Androgen-Dependent Reproductive Development in the Male Rat Toxicol. Sci., August 1, 2003; 74(2): 393 - 406. [Abstract] [Full Text] [PDF]

				J. Killian, K. Pratis, R. J. Clifton, P. G. Stanton, D. M. Robertson, and L. O'Donnell 5{alpha}-Reductase Isoenzymes 1 and 2 in the Rat Testis During Postnatal Development Biol Reprod, May 1, 2003; 68(5): 1711 - 1718. [Abstract] [Full Text] [PDF]

				M. S. Mahendroo, K. M. Cala, D. L. Hess, and D. W. Russell Unexpected Virilization in Male Mice Lacking Steroid 5{alpha}-Reductase Enzymes Endocrinology, November 1, 2001; 142(11): 4652 - 4662. [Abstract] [Full Text] [PDF]

				G. P. H. Leung, S. B. Cheng-Chew, and P. Y. D. Wong Nongenomic effect of testosterone on chloride secretion in cultured rat efferent duct epithelia Am J Physiol Cell Physiol, May 1, 2001; 280(5): C1160 - C1167. [Abstract] [Full Text] [PDF]

				M. S. Marty, J. W. Crissman, and E. W. Carney Evaluation of the Male Pubertal Onset Assay to Detect Testosterone and Steroid Biosynthesis Inhibitors in CD Rats Toxicol. Sci., April 1, 2001; 60(2): 285 - 295. [Abstract] [Full Text] [PDF]

				B. A. Foster and G. R. Cunha Efficacy of Various Natural and Synthetic Androgens to Induce Ductal Branching Morphogenesis in the Developing Anterior Rat Prostate Endocrinology, January 1, 1999; 140(1): 318 - 328. [Abstract] [Full Text]

				M. D. Katz, I. Kligman, L.-Q. Cai, Y.-S. Zhu, C. M. Fratianni, I. Zervoudakis, Z. Rosenwaks, and J. Imperato-McGinley Paternity by Intrauterine Insemination with Sperm from a Man with 5{alpha}-Reductase-2 Deficiency N. Engl. J. Med., April 3, 1997; 336(14): 994 - 998. [Full Text] [PDF]

				F. W. George Androgen Metabolism in the Prostate of the Finasteride-Treated, Adult Rat: A Possible Explanation for the Differential Action of Testosterone and 5{alpha}-Dihydrotestosterone during Development of the Male Urogenital Tract Endocrinology, March 1, 1997; 138(3): 871 - 877. [Abstract] [Full Text] [PDF]