Terada O, Shimada K, Saito N
Laboratory of Animal Physiology, School of Agriculture, Nagoya University, Japan.
J Reprod Fertil. 1997 Sep;111(1):59-64. doi: 10.1530/jrf.0.1110059.
Plasma concentrations of oestradiol and LH and steady-state pituitary concentrations of the mRNAs encoding the LH beta and alpha subunits in the gland were measured at intervals of 1 month for 5 months in female chickens. In addition, feedback regulation by oestradiol of concentrations of mRNAs encoding these LH subunits was studied in ovariectomized young (3-week-old) and adult hens. Concentrations of the mRNAs encoding the LH beta and alpha subunits increased significantly before sexual maturity and the changes were highly correlated with increases in plasma and pituitary concentrations of LH. Ovariectomy significantly reduced circulating plasma concentrations of oestradiol but increased pituitary concentrations of mRNAs encoding LH beta and alpha subunits and pituitary and plasma concentrations of LH in adult laying hens. In addition, in 3-week-old chickens, ovariectomy induced an increase in plasma and pituitary gland concentrations of LH. This ovariectomy-induced mRNA expression and tissue and plasma increases of LH were prevented by oestradiol replacement. These data suggest that a negative feedback mechanism by ovarian oestradiol inhibits LH release from the pituitary and pituitary LH biosynthesis in chickens.
在雌性鸡中，每隔1个月测量一次血浆中雌二醇和促黄体生成素（LH）的浓度以及腺体内编码LHβ和α亚基的mRNA的垂体稳态浓度，持续5个月。此外，还在卵巢切除的幼龄（3周龄）和成年母鸡中研究了雌二醇对这些LH亚基编码mRNA浓度的反馈调节。编码LHβ和α亚基的mRNA浓度在性成熟前显著增加，且这些变化与血浆和垂体中LH浓度的增加高度相关。卵巢切除术显著降低了成年产蛋母鸡循环血浆中雌二醇的浓度，但增加了垂体中编码LHβ和α亚基的mRNA浓度以及垂体和血浆中LH的浓度。此外，在3周龄的鸡中，卵巢切除术导致血浆和垂体中LH浓度增加。雌二醇替代可防止这种卵巢切除诱导的mRNA表达以及LH在组织和血浆中的增加。这些数据表明，卵巢雌二醇的负反馈机制抑制鸡垂体中LH的释放和垂体LH的生物合成。
