Buzzard Jeremy J, Loveland Kate L, O'Bryan Moira K, O'Connor Anne E, Bakker Marilyn, Hayashi Tetsuo, Wreford Nigel G, Morrison John R, de Kretser David M
Monash Institute of Reproduction and Development, Monash University, 27-31 Wright Street, Clayton, Victoria 3168, Australia.
Endocrinology. 2004 Jul;145(7):3532-41. doi: 10.1210/en.2003-1036. Epub 2004 Apr 7.
This study describes the testicular levels of inhibin/activin subunits by Northern analysis and in situ hybridization and serum and testicular levels of inhibins A and B and activin A by enzyme linked immunosorbent assays (ELISA) during postnatal development in the rat. We show that serum inhibin A levels are less than 4 pg/ml throughout postnatal life. Serum inhibin B levels peak at 572 +/- 119 pg/ml (mean +/- se) at d 40 post partum (pp) before falling to 182 +/- 35 pg/ml in mature males. Serum activin A decreases from 294 +/- 29 pg/ml at d 6 to 132 +/- 27 pg/ml at maturity. Within the testis, inhibin A levels fall from 0.330 +/- 0.108 ng/g at d 15 to less than 0.004 ng/g at maturity. Inhibin B levels peak at 43.9 +/- 4.2 ng/g at d 6 before falling to 1.6 +/- 0.13 ng/g at maturity. Testicular activin A levels fall from 18.6 +/- 2.2 ng/g at d 6 to 0.094 +/- 0.013 ng/g at maturity. Northern profiles of testicular inhibin/activin subunits correlate with immunoreactive levels demonstrated by ELISA. In situ hybridization suggests that beta(A) and beta(B) subunit expression is largely restricted to the seminiferous tubule, particularly Sertoli cells, spermatogonia, and primary spermatocytes. These data support the view that inhibin B is the major inhibin in the male rat and that levels relate to Sertoli cell number and activity. Furthermore, the demonstration of high local concentrations of activin A during the period of Sertoli cell proliferation and the onset of spermatogenesis support its proposed role because a modulator of testicular development and function.
本研究通过Northern印迹分析和原位杂交描述了大鼠出生后发育过程中睾丸中抑制素/激活素亚基的水平，并用酶联免疫吸附测定（ELISA）法检测了血清和睾丸中抑制素A和B以及激活素A的水平。我们发现，在整个出生后生命过程中，血清抑制素A水平低于4 pg/ml。血清抑制素B水平在产后第40天达到峰值，为572±119 pg/ml（平均值±标准误），之后在成年雄性大鼠中降至182±35 pg/ml。血清激活素A从第6天的294±29 pg/ml降至成年时的132±27 pg/ml。在睾丸内，抑制素A水平从第15天的0.330±0.108 ng/g降至成年时的低于0.004 ng/g。抑制素B水平在第6天达到峰值，为43.9±4.2 ng/g，之后在成年时降至1.6±0.13 ng/g。睾丸激活素A水平从第6天的18.6±2.2 ng/g降至成年时的0.094±0.013 ng/g。睾丸抑制素/激活素亚基的Northern印迹图谱与ELISA检测的免疫反应水平相关。原位杂交表明，β(A)和β(B)亚基的表达主要局限于生精小管，特别是支持细胞、精原细胞和初级精母细胞。这些数据支持以下观点：抑制素B是雄性大鼠中的主要抑制素，其水平与支持细胞数量和活性有关。此外，在支持细胞增殖和精子发生开始期间激活素A局部高浓度的证明支持了其作为睾丸发育和功能调节剂的作用。
