This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by BONET, B. Articles by HERRERA, E. Search for Related Content PubMed PubMed Citation Articles by BONET, B. Articles by HERRERA, E.

Different Response to Maternal Hypothyroidism during the First and Second Half of Gestation in the Rat^*

Departamento de Bioquímica, Facultad de Medicina, Universidad de Alcalá de Henares and Hospital Ramón y Cajal 28034-Madrid, Spain

Address requests for reprints to: Emilio Herrera, Ph.D., Servicio de Bioquimica, Hospital Ramon y Cajal, Ctra. Colmenar km 9, 28034 Madrid, Spain.

Abstract

Female rats were mated and thyroidectomized (T) on the same day and divided into four groups. Three groups were subsequently treated daily with 1.8 µg L-T₄/100 g body wt: 1) for the first 12 days [T + T₄ (I)]; 2) from the 12th day until death [T + T₄ (II)]; or 3) for the entire 21-day study [T + T₄ (I + 11)]. The other T animals were maintained without treatment (T), and another group of mated rats were sham operated (C). Maternal body weight increase during gestation did not differ between T + T₄ (I + II) and C dams, whereas it was smaller in T dams from the 7th gestational day onward. Neither interruption of T₄ treatment in the T + T₄ (I) rats after the 12th day nor treatment initiated at that time in the T + T₄ (II) group modified their body weights. At day 21, the weights of the maternal conceptus-free body and liver, the placenta, and the fetuses were lower in the T and T + T₄ (II) animals than in either the C and the T + T₄ (I + II) animals. Maternal plasma T₄ and pituitary GH content were reduced, and plasma TSH was enhanced in both T and T + T₄ (I) dams. In fetuses, plasma TSH concentration was augmented in T and T + T₄ (I) rats and unchanged in T -I- T₄ (II) animals when compared with those of T + T₄ (I + II). Pituitary GH content was reduced in T and T + T₄ (II) fetuses and unchanged in the T + T₄ (I) group. We propose that maternal thyroidectomy greatly decreases the thyroid hormone levels in embryonic structures during the first half of gestation and inhibits normal maternal metabolic changes during this period. In addition to interfering with normal fetal development, these effects reduce the quantity of maternal substrates available to fetuses during the last phase of gestation. In contrast, when maternal hypothyroidism occurs during the second half of gestation, the effects are not as detrimental because fetal thyroid gland activity is adequate, and maternal catabolic adaptations are not impaired. (Endocrinology 122: 450–455, 1988)

Footnotes

^* Supported by grants from the Fondo de Investigaciones Sanitarias de la Seguridad Social and from the Comision Asesora de Investigaciones Cientifica y Tecnica, Ministerio de Education y Ciencia of Spain.

Received February 24, 1987.

This article has been cited by other articles:

				J. Slone Wilcoxon and E. E. Redei Prenatal programming of adult thyroid function by alcohol and thyroid hormones Am J Physiol Endocrinol Metab, August 1, 2004; 287(2): E318 - E326. [Abstract] [Full Text] [PDF]

				M. P. Ramos, M. D. Crespo-Solans, S. del Campo, J. Cacho, and E. Herrera Fat accumulation in the rat during early pregnancy is modulated by enhanced insulin responsiveness Am J Physiol Endocrinol Metab, August 1, 2003; 285(2): E318 - E328. [Abstract] [Full Text] [PDF]

				J. H. Oppenheimer and H. L. Schwartz Molecular Basis of Thyroid Hormone-Dependent Brain Development Endocr. Rev., August 1, 1997; 18(4): 462 - 475. [Abstract] [Full Text] [PDF]

				H. L. Schwartz, M. E. Ross, and J. H. Oppenheimer Lack of Effect of Thyroid Hormone on Late Fetal Rat Brain Development Endocrinology, August 1, 1997; 138(8): 3119 - 3124. [Abstract] [Full Text] [PDF]