Allenby G, Foster P M, Sharpe R M
Medical Research Council Reproductive Biology Unit, Centre for Reproductive Biology, Edinburgh, Scotland.
Endocrinology. 1991 Jan;128(1):467-76. doi: 10.1210/endo-128-1-467.
This study has assessed whether depletion of specific germ cell types is able to alter the secretion of immunoactive inhibin by adult Sertoli cells in vivo and in vitro. Pachytene and later spermatocytes were depleted (80-100%) by a single administration of methoxy acetic acid (MAA; 650 mg/kg) to adult rats. At intervals between 1 and 42 days posttreatment, rats were killed, and the blood levels of FSH, LH, and testosterone were determined together with the levels of immunoactive inhibin in plasma and testicular interstitial fluid (IF). At the same time intervals, seminiferous tubules (ST; 5 x 2 cm) were isolated from control and MAA-treated rats and cultured for 24-72 h in the presence or absence of rat FSH, (Bu)2cAMP, or MAA under rigorously optimized conditions. The hormonal changes observed were related to the presence/absence of specific germ cell types, as determined by assessment of testicular morphology in perfusion-fixed testes from similarly treated rats. One to 3 days after MAA treatment, coincident with the depletion of pachytene spermatocytes, blood levels of FSH were increased significantly compared with controls; FSH returned to control levels at 7-14 days (when early spermatids were depleted), but were increased again at 21-35 days (when late spermatids were depleted). In contrast, while the plasma levels of immunoactive inhibin were increased 2-fold 3 days posttreatment, they were comparable to controls at 7-14 days, but were decreased substantially at 21-28 days. The levels of immunoactive inhibin in testicular IF were more than doubled 1 and 3 days posttreatment, but were comparable to control levels at all other times. Blood levels of LH showed a similar pattern of change to FSH, although only at 21-28 days after MAA treatment was there a significant increase, while blood levels of testosterone were comparable at all times in control and MAA-treated rats. To confirm that the changes observed in vivo after MAA treatment were indicative of changes in Sertoli rather than Leydig cell secretion of immonoactive inhibin, its secretion by isolated ST was assessed, and a pattern of change similar to that in plasma was observed. Thus, when cultured for 24 h under basal conditions, ST from rats 1-3 days after MAA treatment showed a 2- to 3-fold increase in secretion of immunoactive inhibin, which returned to control levels at 7-14 days before being reduced substantially at 21-28 days and then recovering to control levels; similar changes were observed for FSH- and (Bu)2cAMP-stimulated secretion of immunoactive inhibin.(ABSTRACT TRUNCATED AT 400 WORDS)
本研究评估了特定生殖细胞类型的缺失是否能够在体内和体外改变成年支持细胞免疫活性抑制素的分泌。通过向成年大鼠单次注射甲氧基乙酸（MAA；650mg/kg），使粗线期及更晚期的精母细胞减少（80 - 100%）。在处理后的1至42天内，每隔一段时间处死大鼠，测定血浆中促卵泡激素（FSH）、促黄体生成素（LH）和睾酮的水平，以及血浆和睾丸间质液（IF）中免疫活性抑制素的水平。在相同的时间间隔，从对照大鼠和经MAA处理的大鼠中分离出曲细精管（ST；5×2cm），并在严格优化的条件下，在有或无大鼠FSH、双丁酰环磷腺苷（Bu）2cAMP或MAA存在的情况下培养24 - 72小时。观察到的激素变化与特定生殖细胞类型的存在与否相关，这是通过对同样处理的大鼠灌注固定睾丸的形态学评估来确定的。MAA处理后1至3天，与粗线期精母细胞的减少同时发生，FSH的血水平与对照相比显著升高；FSH在7至14天（此时早期精子细胞减少）恢复到对照水平，但在21至35天（此时晚期精子细胞减少）再次升高。相比之下，免疫活性抑制素的血浆水平在处理后3天增加了2倍，但在7至14天与对照相当，但在21至28天大幅下降。睾丸IF中免疫活性抑制素的水平在处理后1天和3天增加了一倍多，但在所有其他时间与对照水平相当。LH的血水平显示出与FSH相似的变化模式，尽管仅在MAA处理后21至28天有显著升高，而对照大鼠和经MAA处理的大鼠的睾酮血水平在所有时间都相当。为了证实MAA处理后在体内观察到的变化表明是支持细胞而非间质细胞分泌免疫活性抑制素发生了变化，对分离的ST的分泌进行了评估，观察到了与血浆中相似的变化模式。因此，在基础条件下培养24小时时，MAA处理后1至3天大鼠的ST显示免疫活性抑制素分泌增加2至3倍，在7至14天恢复到对照水平，然后在21至28天大幅降低，随后恢复到对照水平；FSH和（Bu）2cAMP刺激的免疫活性抑制素分泌也观察到类似变化。（摘要截选至400字）
