Baldwin D M, Roser J F, Muyan M, Lasley B, Dybdal N
Department of Veterinary Medical Reproduction, University of California, Davis 95616.
J Reprod Fertil Suppl. 1991;44:327-32.
Enzymatically dispersed anterior pituitary cells from donor mares were cultured for 48 h in alpha-modified Eagles' medium containing 10% steroid-free horse serum. The cells were then incubated for 24 h in fresh medium oestrogen followed by a 4-h incubation with or without GnRH. Media and cell extracts were analyzed for LH by radioimmunoassay. In the first series of experiments, pituitary cells from Day-3 dioestrous mares were preincubated with ethanol (control) or different concentrations of E2 (10(-11) to 10(-7) M) for 24 h prior to a 4-h incubation without (basal) or with 1.0 nM GnRH. E2 increased (P less than 0.001) GnRH-stimulated LH release with a maximal response obtained at 10(-10) M E2 with an ED50 of 3 x 10(-11) M E2. Also E2 enhanced greatly the responsiveness of the pituitary to varying concentrations of GnRH by decreasing the minimum effective dose and ED50 by 93% and 78%, respectively, and by increasing the maximum response to GnRH by 250%. E2 had no effect on basal LH secretion. In a second experiment, the effects of E2, E1 and E1S on basal and GnRH stimulated LH release were evaluated. Although E1 increased GnRH-stimulated LH release, the maximally effective dose of E1 to enhance LH release and the ED50 for E1 were 100 times greater than those found for E2. E1S had no oestrogenic activity even at concentrations as high as 100 nM.(ABSTRACT TRUNCATED AT 250 WORDS)
将来自供体母马的经酶分散的垂体前叶细胞，在含有10%无类固醇马血清的α-改良伊格尔培养基中培养48小时。然后将细胞在含雌激素的新鲜培养基中孵育24小时，接着在有或无促性腺激素释放激素（GnRH）的情况下孵育4小时。通过放射免疫测定法分析培养基和细胞提取物中的促黄体生成素（LH）。在第一系列实验中，来自发情后期第3天母马的垂体细胞，在无（基础）或有1.0 nM GnRH孵育4小时之前，先用乙醇（对照）或不同浓度的雌二醇（E2，10^(-11)至10^(-7) M）预孵育24小时。E2增加了（P<0.001）GnRH刺激的LH释放，在10^(-10) M E2时获得最大反应，E2的半数有效剂量（ED50）为3×10^(-11) M。此外，E2通过将最小有效剂量和ED50分别降低93%和78%，并将对GnRH的最大反应增加250%，极大地增强了垂体对不同浓度GnRH的反应性。E2对基础LH分泌无影响。在第二个实验中，评估了E2、雌酮（E1）和硫酸雌酮（E1S）对基础和GnRH刺激的LH释放的影响。尽管E1增加了GnRH刺激的LH释放，但E1增强LH释放的最大有效剂量和E1的ED50比E2的高100倍。即使在高达100 nM的浓度下，E1S也没有雌激素活性。（摘要截短于250字）
