Campbell B K, McNeilly A S, Mann G E, Baird D T
Department of Obstetrics and Gynaecology, University of Edinburgh, Scotland.
Biol Reprod. 1991 Mar;44(3):483-90. doi: 10.1095/biolreprod44.3.483.
Twenty-four Scottish Blackface ewes (mean weight 50.0 +/- 0.1 kg with ovulation rate 1.3 +/- 0.1) were randomly divided into 4 groups of 6 animals. Under general anesthesia, following the collection of a timed sample of ovarian venous blood, the ovaries of these animals were collected either on Day 10 of the luteal phase or 12, 24, and 48 h after a luteolytic dose of a prostaglandin (PG) F2 alpha analogue (cloprostenol 100 micrograms i.m.) administered on Day 10. All follicles greater than 3 mm were dissected from the ovaries and incubated in Medium 199 (M199) at 37 degrees C for 2 h, following which the granulosa cells were harvested and incubated in triplicate for 24 h in M199 with or without ovine FSH or ovine LH. Plasma and culture media samples were assayed for inhibin, estradiol (E2), androstenedione (A4), and testosterone (T) by specific RIA. After correcting for hematocrit, ovarian secretion rates were calculated from the product of the plasma concentration and flow rate. The rate of ovarian inhibin secretion during the luteal phase was similar from ovaries categorized on the basis of presence of luteal tissue (1.0 +/- 0.3 and 0.9 +/- 0.5 ng/min for CL present and absent, respectively), confirming that the ovine CL does not secrete appreciable amounts of inhibin. Inhibin secretion was higher (p less than 0.05) at 12 h after PG-induced luteolysis but not at 24 or 48 h compared to values for luteal phase control ewes. Although ovaries containing large estrogenic follicles (greater than or equal to 4 mm in diameter and classified as estrogenic from in vitro criteria) secreted the most inhibin (55%; p less than 0.05), both ovaries containing large nonestrogenic follicles (33%) and small (11%; less than 4 mm in diameter) follicles secreted appreciable amounts of inhibin. This contrasted strongly with E2 where greater than 80% of the steroid was secreted by large estrogenic follicles. The rate of ovarian inhibin secretion was positively correlated (p less than 0.05) with the rate of E2, A4, and T secretion. Overall, there was no significant effect of stage of cycle on follicular inhibin content after 2 h incubation in vitro, release of inhibin by follicles incubated in vitro, or synthesis of inhibin by granulosa cells cultured in vitro. FSH and LH had no effect on the production of either inhibin or estradiol by cultured granulosa cells. Follicular diameter was positively correlated (p less than 0.001) with follicular inhibin and steroid release. Follicular inhibin content after 2 h incubation in vitro was more highly correlated with inhibin release by incubated follicles (r = 0.7; p less than 0.001) than with inhibin synthesis by granulosa cells in vitro (0.4; p less than 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)
24只苏格兰黑脸母羊（平均体重50.0±0.1千克，排卵率1.3±0.1）被随机分为4组，每组6只。在全身麻醉下，采集定时的卵巢静脉血样本后，这些动物的卵巢于黄体期第10天或在第10天注射溶黄体剂量的前列腺素（PG）F2α类似物（氯前列醇100微克，肌肉注射）后12、24和48小时采集。将所有直径大于3毫米的卵泡从卵巢中分离出来，在37℃的199培养基（M199）中孵育2小时，之后收获颗粒细胞，并在含或不含绵羊促卵泡素（FSH）或绵羊促黄体素（LH）的M199中一式三份孵育24小时。通过特异性放射免疫分析法（RIA）检测血浆和培养基样本中的抑制素、雌二醇（E2）、雄烯二酮（A4）和睾酮（T）。校正血细胞比容后，根据血浆浓度和流速的乘积计算卵巢分泌率。根据黄体组织的有无对卵巢进行分类，黄体期卵巢抑制素的分泌率相似（黄体组织存在和不存在时分别为1.0±0.3和0.9±0.5纳克/分钟），证实绵羊黄体不分泌大量抑制素。与黄体期对照母羊相比，PG诱导溶黄后12小时抑制素分泌较高（p<0.05），但在24或48小时则不然。尽管含有大的雌激素生成卵泡（直径大于或等于4毫米，根据体外标准分类为雌激素生成卵泡）的卵巢分泌的抑制素最多（55%；p<0.05），但含有大的非雌激素生成卵泡（33%）和小卵泡（11%；直径小于4毫米）的卵巢也分泌可观量的抑制素。这与E2形成强烈对比，E2中超过80%的类固醇由大的雌激素生成卵泡分泌。卵巢抑制素分泌率与E2、A4和T分泌率呈正相关（p<0.05）。总体而言，体外孵育2小时后，周期阶段对卵泡抑制素含量、体外孵育卵泡释放抑制素或体外培养颗粒细胞合成抑制素均无显著影响。FSH和LH对培养的颗粒细胞产生抑制素或雌二醇均无影响。卵泡直径与卵泡抑制素和类固醇释放呈正相关（p<0.001）。体外孵育2小时后卵泡抑制素含量与孵育卵泡释放抑制素的相关性（r = 0.7；p<0.001）高于与体外颗粒细胞合成抑制素的相关性（0.4；p<0.01）。（摘要截短至400字）
