Wang X N, Greenwald G S
Department of Physiology, Ralph L. Smith Research Center, University of Kansas Medical Center, Kansas City 66103.
Biol Reprod. 1993 Mar;48(3):585-94. doi: 10.1095/biolreprod48.3.585.
The effects of hypophysectomy (HX) on folliculogenesis, oocyte growth, and ovarian FSH and LH receptors were examined by histology, topical autoradiography, and in vitro incubation of isolated follicles with [3H]thymidine. At random stages of the estrous cycle, mice were HX (Day 0), and they were killed from 0 to 20 days thereafter. Four days after HX, the number of preantral (stages 1-3) and antral (stages 4-5) follicles per ovary was reduced by 40% to 60% compared to Day 0 values, and stage 6 (large preovulatory) follicles had vanished. By Day 20 after HX, the numbers of follicles at stages 1, 2, and 4 were comparable to Day 4 values, whereas stage 3 and 5 follicles were still further diminished to 30% and 15% of Day 0 values, respectively. The number of atretic follicles from Days 0 to 20 after HX did not differ for follicles of stages 3-5, and stage 1 and 2 follicles were all healthy. However, oocyte growth was not coordinated with follicular growth after HX; the oocytes of stage 2-4 follicles were significantly larger than Day 0 oocytes. The enlarged oocytes appeared normal as judged by light and electron microscopy. DNA synthesis for stage 1-3 follicles declined significantly from Days 4 to 20 compared with Day 0 values, but did not change for stage 4 and 5 follicles, since atretic follicles at these stages were still labeled by [3H]thymidine and this was rare for Day 0 follicles. Topical autoradiography for [125I]-labeled FSH and hCG showed that follicular receptors for both hormones declined by Day 4 of HX and remained undetectable thereafter, except for trace amounts of [125I]-hCG binding in the interstitium. The decrease in follicular DNA synthesis and the greater diameter of oocytes in preantral follicles after HX suggest that longer transit times are required for one stage to progress to the next because of the anhormonal environment of the growing follicle. These results provide concrete evidence that pituitary gonadotropins are essential in the mouse for initiation, proliferation, and differentiation of all stages of growing follicles.
通过组织学、局部放射自显影以及用[3H]胸腺嘧啶核苷对分离的卵泡进行体外培养，研究了垂体切除术（HX）对卵泡发生、卵母细胞生长以及卵巢促卵泡激素（FSH）和促黄体生成素（LH）受体的影响。在动情周期的随机阶段，对小鼠进行垂体切除术（第0天），并在术后0至20天处死小鼠。垂体切除术后4天，与第0天的值相比，每个卵巢中窦前卵泡（1 - 3期）和窦卵泡（4 - 5期）的数量减少了40%至60%，6期（大的排卵前）卵泡消失。垂体切除术后20天，1、2和4期卵泡的数量与术后4天的值相当，而3期和5期卵泡分别进一步减少至第0天值的30%和15%。垂体切除术后0至20天，3 - 5期卵泡的闭锁卵泡数量没有差异，1期和2期卵泡均健康。然而，垂体切除术后卵母细胞的生长与卵泡的生长不协调；2 - 4期卵泡的卵母细胞明显大于第0天的卵母细胞。通过光学显微镜和电子显微镜判断，增大的卵母细胞看起来正常。与第0天的值相比，1 - 3期卵泡的DNA合成在术后4至20天显著下降，但4期和5期卵泡的DNA合成没有变化，因为这些阶段的闭锁卵泡仍被[3H]胸腺嘧啶核苷标记，而这在第0天的卵泡中很少见。用[125I]标记的FSH和hCG进行局部放射自显影显示，垂体切除术后4天，两种激素的卵泡受体均下降，此后一直未检测到，除了间质中有微量的[125I] - hCG结合。垂体切除术后卵泡DNA合成的减少以及窦前卵泡中卵母细胞直径的增大表明，由于生长卵泡的无激素环境，一个阶段进展到下一个阶段需要更长的过渡时间。这些结果提供了确凿的证据，表明垂体促性腺激素对小鼠生长卵泡所有阶段的起始、增殖和分化至关重要。
