Maran R R, Ravichandran K, Arunakaran J, Aruldhas M M
Department of Endocrinology, University of Madras, Taramani, Chennai, India.
Endocr Res. 2001 Feb-May;27(1-2):119-41. doi: 10.1081/erc-100107175.
We have previously demonstrated that neonatal and transient neonatal hypothyroidism modulates Leydig, Sertoli, and germ cell numbers, sex steroids and androgen binding protein concentration. The present study was undertaken to study the effect of neonatal onset hypothyroidism on Leydig and peritubular myoid cell numbers, plasma and testicular interstitial fluid (TIF) sex steroid concentration at different age groups of Wistar rats. Hypothyroidism was induced by giving 0.05% methimazole (MMI) to lactating mothers or directly to the male pups from day 1 postpartum through days 10, 15, 30, 40 and 60 postpartum. To confirm hypothyroidism, plasma thyroid hormones and TSH were assayed. Plasma and TIF testosterone, progesterone, dihydrotestosterone (DHT) and estradiol were assayed by radioimmunoassay. Leydig cell number in hypothyroid rats were less than the age-matched controls. The diameter of Leydig cells in hypothyroid rats was smaller than the controls but 10 days old hypothyroids alone had larger than control rats. A significant decrease of peritubular myoid cell number was observed in 30, 40 and 60 days hypothyroid rats and increased in 10 and 15 days hypothyroidism. Hypothyroid rats had elevated level of plasma LH and decreased GH (except day 10 postpartum). Plasma PRL level was increased in 10 and 15 days hypothyroid rats and an opposite effect was observed in 40 and 60 days hypothyroidism. Plasma testosterone, DHT and estradiol were decreased in all hypothyroid rats. However, plasma progesterone level in hypothyroid rats was significantly higher at days 10, 30, and 40 postpartum and an opposite effect was seen in 15 and 60 days experimental groups. TIF testosterone and progesterone titre showed a consistent decrease in hypothyroid rats irrespective of the duration. In hypothyroid rats, TIF DHT levels decreased significantly in days 10, 40 and 60 postpartum. However, it increased in days 15 and 30 postpartum. Except at day 10 postpartum, the level of TIF estradiol in hypothyroid rats was significantly less than their age matched controls. Our data clearly indicate that neonatal onset hypothyroidism adversely affect Leydig cell proliferation along with impaired steroidogenesis.
我们之前已经证明，新生儿期和短暂的新生儿甲状腺功能减退会调节睾丸间质细胞、支持细胞和生殖细胞数量、性类固醇以及雄激素结合蛋白浓度。本研究旨在探讨新生儿期甲状腺功能减退对不同年龄组Wistar大鼠睾丸间质细胞和睾丸肌样细胞数量、血浆和睾丸间质液（TIF）中性类固醇浓度的影响。通过给哺乳期母鼠喂食0.05%甲巯咪唑（MMI）或从产后第1天起直接给雄性幼鼠喂食，持续至产后第10、15、30、40和60天来诱导甲状腺功能减退。为确认甲状腺功能减退，检测血浆甲状腺激素和促甲状腺激素。采用放射免疫分析法检测血浆和TIF中的睾酮、孕酮、双氢睾酮（DHT）和雌二醇。甲状腺功能减退大鼠的睾丸间质细胞数量少于年龄匹配的对照组。甲状腺功能减退大鼠的睾丸间质细胞直径小于对照组，但仅10日龄的甲状腺功能减退大鼠的睾丸间质细胞直径大于对照大鼠。在30、40和60日龄的甲状腺功能减退大鼠中观察到睾丸肌样细胞数量显著减少，而在10和15日龄的甲状腺功能减退大鼠中则增加。甲状腺功能减退大鼠的血浆促黄体生成素（LH）水平升高，生长激素（GH）水平降低（产后第10天除外）。在10和15日龄的甲状腺功能减退大鼠中血浆催乳素（PRL）水平升高，而在40和60日龄的甲状腺功能减退大鼠中观察到相反的作用。所有甲状腺功能减退大鼠的血浆睾酮、DHT和雌二醇水平均降低。然而，甲状腺功能减退大鼠的血浆孕酮水平在产后第10、30和40天显著升高，而在15和60日龄的实验组中观察到相反的作用。无论持续时间如何，甲状腺功能减退大鼠的TIF睾酮和孕酮滴度均持续下降。在甲状腺功能减退大鼠中，产后第10、40和60天TIF中的DHT水平显著降低。然而，在产后第15和30天则升高。除产后第10天外，甲状腺功能减退大鼠的TIF雌二醇水平显著低于其年龄匹配的对照组。我们的数据清楚地表明，新生儿期甲状腺功能减退会对睾丸间质细胞增殖产生不利影响，并伴有类固醇生成受损。
