Mann G E, McNeilly A S, Baird D T
Department of Obstetrics and Gynaecology, University of Edinburgh.
J Endocrinol. 1992 Feb;132(2):225-34. doi: 10.1677/joe.0.1320225.
This experiment was undertaken in order to investigate the production of inhibin, oestradiol and androstenedione by ovarian follicles at different stages of the oestrous cycle in sheep. Twenty-four Scottish Blackface ewes were allocated to four groups of six ewes, i.e. those operated on during the luteal phase (day 10), and those operated on during the follicular phase 24-30, 36 and 60 h after the induction of luteal regression by an injection of 125 micrograms cloprostenol on day 10 of the luteal phase. Samples of jugular and ovarian venous blood were collected under anaesthesia and ovaries were then removed and all follicles larger than 3 mm diameter dissected out and incubated in medium for 2 h. After injection of cloprostenol, luteal regression occurred as indicated by a fall in the secretion rate of progesterone. The ovarian secretion rate of inhibin was similar at all stages of the follicular phase and during the luteal phase while, in contrast, the secretion rate of oestradiol was significantly (P less than 0.05) elevated in the group 24 h after injection of cloprostenol. There was good correlation between the in-vivo ovarian secretion rate and production rate during incubation in vitro for both inhibin (r = 0.57) and oestradiol (r = 0.60). When follicle diameter was compared with in-vitro hormone production there was good correlation for inhibin (r = 0.72) with larger follicles producing more inhibin, while the value for oestradiol was somewhat lower (r = 0.57) owing to the presence of large atretic follicles with low oestradiol production. Androstenedione production showed a lower correlation with follicle diameter (r = 0.39). When the four time periods were compared separately, there were significantly (P less than 0.05) more follicles with high in-vitro oestradiol production (greater than 90 fmol/min) in the group at 36 h than in the other three groups, while inhibin release in relation to follicle size was similar in the four groups. Large oestrogenic follicles were responsible for 90% of the total oestradiol production during culture while only providing 55% of the total inhibin production, with large non-oestrogenic and small follicles contributing 33% and 12% of inhibin production respectively. From the results of this study we conclude that while oestradiol is mainly produced by the large oestrogenic follicles, a considerable amount of inhibin is also produced by large non-oestrogenic and small follicles.(ABSTRACT TRUNCATED AT 400 WORDS)
本实验旨在研究绵羊发情周期不同阶段卵巢卵泡中抑制素、雌二醇和雄烯二酮的产生情况。将24只苏格兰黑脸母羊分为四组，每组6只，即黄体期（第10天）进行手术的母羊，以及在黄体期第10天注射125微克氯前列醇诱导黄体退化后24 - 30小时、36小时和60小时进行手术的卵泡期母羊。在麻醉状态下采集颈静脉血和卵巢静脉血样本，然后切除卵巢，将所有直径大于3毫米的卵泡解剖出来，在培养基中孵育2小时。注射氯前列醇后，孕酮分泌率下降表明黄体退化发生。卵泡期所有阶段和黄体期的卵巢抑制素分泌率相似，相比之下，注射氯前列醇后24小时组的雌二醇分泌率显著升高（P < 0.05）。抑制素（r = 0.57）和雌二醇（r = 0.60）的体内卵巢分泌率与体外孵育时的产生率之间均具有良好的相关性。当将卵泡直径与体外激素产生情况进行比较时，抑制素的相关性良好（r = 0.72），较大的卵泡产生更多的抑制素，而由于存在大量雌二醇产生量低的闭锁大卵泡，雌二醇的相关性值略低（r = 0.57）。雄烯二酮的产生与卵泡直径的相关性较低（r = 0.39）。当分别比较四个时间段时，36小时组体外雌二醇产生量高（大于90 fmol/分钟）的卵泡数量显著多于其他三组（P < 0.05），而四组中与卵泡大小相关的抑制素释放情况相似。培养期间，大的雌激素生成卵泡占雌二醇总产生量的90%，而仅占抑制素总产生量的55%，大的非雌激素生成卵泡和小卵泡分别占抑制素产生量的33%和12%。从本研究结果我们得出结论，虽然雌二醇主要由大的雌激素生成卵泡产生，但大量的抑制素也由大的非雌激素生成卵泡和小卵泡产生。（摘要截选至400字）
