In utero exposure of female lambs to testosterone reduces the sensitivity of the gonadotropin-releasing hormone neuronal network to inhibition by progesterone.
In utero exposure of female lambs to testosterone reduces the sensitivity of the gonadotropin-releasing hormone neuronal network to inhibition by progesterone.
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雌性羔羊在子宫内接触睾酮会降低促性腺激素释放激素神经元网络对黄体酮抑制的敏感性。
作者：
Jane E. Robinson;R. Forsdike;James A. Taylor
母羊胎儿在妊娠早期暴露于外源性雄激素会使成年母羊的生殖解剖、生理和行为永久地雄性化。子宫内睾酮暴露已被证明对GnRH神经元网络起中枢作用，从而改变对雌激素刺激和抑制作用的反应。目前尚不清楚胎儿雄激素是否会改变其他对GnRH释放调节至关重要的机制，特别是其他重要的调节类固醇反馈回路。我们对去性腺的青春期后绵羊进行了三项研究，以确定黄体酮对偶发性LH释放的抑制作用是否也是性别特异性的，是否由子宫早期暴露于睾酮引起。在每项研究中，测定了孕酮释放CIDR装置植入前后的LH释放脉动模式。研究涉及7只母羊、7只公羊和12只雄激素化母羊（T60 （n = 7）和T30 （n = 5）组）；从怀孕第30-90天或第60-90天，每周给母亲服用200毫克丙酸睾酮，分别为60或30天。前两项研究是在雌二醇低循环浓度存在（实验1）或不存在（实验2）的发情季节进行的。实验3在没有外源雌激素的繁殖季节进行。在所有三项研究中，黄体酮仅在女性中抑制黄体生成素脉冲频率。黄体酮对雄性或两组雄激素化母羊的平均黄体生成素浓度或黄体生成素脉冲的频率和振幅没有影响。我们的结论是，黄体酮对偶发性LH释放的抑制在绵羊中是性别分化的，雄性对类固醇负反馈的反应比雌性弱。此外，这些性别差异是在怀孕147天的第60天和第90天之间，子宫内暴露于雄激素的短短30天的结果。
Exposure of the female ovine fetus to exogenous androgens during early gestation permanently masculinizes the reproductive anatomy, physiology, and behavior of the adult ewe. In utero testosterone exposure has been shown to act centrally on the GnRH neuronal network to alter the response to both the stimulatory and inhibitory actions of estrogen. It is currently unknown whether fetal androgens alter other mechanisms that are critical for the regulation of GnRH release and, specifically, other important regulatory steroid feedback loops. Three studies were performed on gonadectomized postpubertal sheep to determine whether the inhibitory actions of progesterone on episodic LH release are also sex-specific and engendered by early in utero exposure to testosterone. In each study, the pulsatile pattern of LH release was determined both before and after the sc implantation of a progesterone releasing CIDR device. The studies involved 7 female, 7 male, and 12 androgenized female sheep (T60 (n = 7) and T30 (n = 5) groups; 200 mg testosterone propionate/week im to the mother for 60 or 30 days, respectively, from day 30-90 or 60-90 of pregnancy). The first two studies were performed in the anestrous season in the presence (Exp 1) or absence (Exp 2) of a low circulating concentration of estradiol. Exp 3 was carried out in the breeding season in the absence of exogenous estrogen. In all three studies progesterone inhibited LH pulse frequency only in the females. Progesterone had no action on mean LH concentrations or the frequency or amplitude of LH pulses in the males or either group of androgenized ewes. We conclude that the inhibition of episodic LH release by progesterone is sexually differentiated in the sheep, males being less responsive than females to steroid negative feedback. Further, these sex differences are a consequence of in utero exposure to androgens for a period as short as 30 days between days 60 and 90 of a 147-day pregnancy.
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产前睾酮在发育中的绵羊中使黄体生成素分泌的强直和激增模式差异雄性化。
影响因子：
4.1
作者：
Wood,RI;Mehta,V;Herbosa,CG;Foster,DL
通讯作者：
Foster,DL
促性腺激素释放激素神经元突触输入的性别二态性。
影响因子：
4.8
作者：
Chen,WP;Witkin,JW;Silverman,AJ
通讯作者：
Silverman,AJ
影响因子：
3.6
作者：
GOODMAN, RL;BITTMAN, EL;KARSCH, FJ
通讯作者：
KARSCH, FJ
产前雄激素影响神经内分泌性成熟。
影响因子：
4.8
作者：
Wood,RI;Ebling,FJ;I'Anson,H;Bucholtz,DC;Yellon,SM;Foster,DL
通讯作者：
Foster,DL
影响因子：
4.8
作者：
J. Z. Kasa-Vubu;G E Dahl;N. P. Evans;L. Thrun;S. Moenter;Vasantha Padmanabhan;F. Karsch
通讯作者：
J. Z. Kasa-Vubu;G E Dahl;N. P. Evans;L. Thrun;S. Moenter;Vasantha Padmanabhan;F. Karsch