Sun Y T, Robertson D M, Gonzales G, Risbridger G P, de Kretser D M
Department of Anatomy, Monash University, Clayton, Victoria, Australia.
J Reprod Fertil. 1989 Nov;87(2):795-801. doi: 10.1530/jrf.0.0870795.
Intact and hypophysectomized rats were treated with graded doses of testosterone via subcutaneous Silastic implants over a 13-week period. Serum inhibin concentrations fell 50% (P less than 0.001) after 2 weeks of hypophysectomy, remaining suppressed at this level for 13 weeks. The administration of testosterone to hypophysectomized rats (serum testosterone values 2-12 ng/ml; control values 5.5 ng/ml) was without effect on serum inhibin values. In contrast, administration of testosterone to intact animals for 7 weeks resulted in an initial fall (P less than 0.05) in inhibin levels to 50-70% of controls then increasing to reach control levels at higher doses. Serum FSH concentrations were similarly biphasic with increasing dose of testosterone and values for these two hormones were significantly correlated (r = 0.44, P less than 0.01). Segments of seminiferous tubules in culture from rats after various times of hypophysectomy showed a partly suppressed secretion of inhibin. The administration of testosterone did not modify inhibin production although inhibin production was sensitive to FSH. It is concluded that (1) serum inhibin concentrations are partly suppressed after hypophysectomy and testosterone has no effect on serum inhibin values; and (2) the suppression of serum inhibin in intact rats treated with increasing doses of testosterone is attributable to the concomitant fall in serum FSH concentrations.
完整大鼠和垂体切除大鼠通过皮下硅橡胶植入物接受不同剂量的睾酮治疗，为期13周。垂体切除术后2周，血清抑制素浓度下降50%（P<0.001），并在该水平维持抑制状态13周。给垂体切除大鼠注射睾酮（血清睾酮值为2 - 12 ng/ml；对照值为5.5 ng/ml）对血清抑制素值无影响。相反，给完整动物注射睾酮7周导致抑制素水平最初下降（P<0.05）至对照水平的50 - 70%，然后在较高剂量时升至对照水平。血清促卵泡激素（FSH）浓度随睾酮剂量增加呈现类似的双相变化，这两种激素的值显著相关（r = 0.44，P<0.01）。垂体切除术后不同时间大鼠的培养生精小管片段显示抑制素分泌部分受抑制。尽管抑制素产生对FSH敏感，但睾酮给药并未改变抑制素的产生。结论为：（1）垂体切除术后血清抑制素浓度部分受抑制，睾酮对血清抑制素值无影响；（2）在给完整大鼠注射递增剂量睾酮时血清抑制素的抑制归因于血清FSH浓度的相应下降。
