Pineau C, Sharpe R M, Saunders P T, Gérard N, Jégou B
Groupe d'Etude de la Fonction de Reproduction chez le Mâle, UA CNRS 256, Université de Rennes I, Campus de Beaulieu, France.
Mol Cell Endocrinol. 1990 Jul 30;72(1):13-22. doi: 10.1016/0303-7207(90)90235-z.
To elucidate the endocrine and paracrine regulation of testicular inhibin production, the effects of follicle-stimulating hormone (FSH), (Bu)2cAMP, germ cells (either crude or enriched preparations) and germ cell-conditioned media on inhibin production (immuno- and bio-activities) and the levels of alpha- and beta B-subunit mRNAs were assessed in cultured Sertoli cells isolated from 20-day-old rats. FSH and (Bu)2-cAMP stimulated both secreted and intracellular inhibin levels in a dose-dependent manner. Using cDNA probes corresponding to the alpha-subunit and the beta B-subunit of rat inhibin it was also shown that both FSH and (Bu)2cAMP markedly increased the level of alpha-subunit mRNA but had no effect on the beta B-subunit mRNA. Addition of a crude mixture of germ cells to Sertoli cell monolayers was found to enhance inhibin secretion. Of the different germ cell fractions tested in co-culture, early spermatids reproducibly stimulated both basal and (Bu)2cAMP-induced production of inhibin whereas pachytene spermatocytes only increased the latter; cytoplasts from elongated spermatids (CES) had no effect. Co-culture of Sertoli cells with liver epithelial cells (LEC) significantly enhanced (Bu)2cAMP-induced inhibin levels. Media conditioned by early spermatids consistently and dramatically stimulated the secretion of both bioactive and immunoactive inhibin by Sertoli cells while spent media from pachytene spermatocytes displayed less activity. CES-conditioned media had only minor stimulatory effects, which may have resulted from the contamination of this fraction by spermatids. Media conditioned by LEC had no effect on inhibin production, confirming that the activity of this cell line is not mediated via a diffusible factor. Early spermatids were found to increase levels of the alpha-subunit mRNA. The current study provides evidence for the involvement of germ cells, in particular of early spermatids, in the local testicular regulation of inhibin gene expression and production in the rat. This may be of crucial importance for the ontogeny of this parameter of Sertoli cell function, and has important implications with regard to the postulated endocrine and paracrine roles of inhibin.
为阐明睾丸抑制素产生的内分泌和旁分泌调节机制，研究了促卵泡激素（FSH）、双丁酰环磷腺苷（Bu）2cAMP、生殖细胞（粗制或富集制剂）及生殖细胞条件培养基对从20日龄大鼠分离的培养支持细胞中抑制素产生（免疫活性和生物活性）以及α亚基和βB亚基mRNA水平的影响。FSH和（Bu）2cAMP以剂量依赖方式刺激分泌型和细胞内抑制素水平。使用与大鼠抑制素α亚基和βB亚基对应的cDNA探针还表明，FSH和（Bu）2cAMP均显著提高α亚基mRNA水平，但对βB亚基mRNA无影响。发现向支持细胞单层中添加生殖细胞粗混合物可增强抑制素分泌。在共培养中测试的不同生殖细胞组分中，早期精子细胞可重复性地刺激基础和（Bu）2cAMP诱导的抑制素产生，而粗线期精母细胞仅增加后者；伸长精子细胞的胞质体（CES）则无作用。支持细胞与肝上皮细胞（LEC）共培养显著提高（Bu）2cAMP诱导的抑制素水平。早期精子细胞条件培养基持续且显著刺激支持细胞分泌生物活性和免疫活性抑制素，而粗线期精母细胞的用过培养基活性较低。CES条件培养基仅有轻微刺激作用，这可能是由于该组分被精子细胞污染所致。LEC条件培养基对抑制素产生无影响，证实该细胞系的活性不是通过可扩散因子介导的。发现早期精子细胞可增加α亚基mRNA水平。本研究为生殖细胞，特别是早期精子细胞参与大鼠睾丸局部抑制素基因表达和产生的调节提供了证据。这对于支持细胞功能这一参数的个体发生可能至关重要，并且对于抑制素假定的内分泌和旁分泌作用具有重要意义。
