Nitric oxide production of rat Leydig and Sertoli cells is stimulated by round spermatid factor(s)

In this study, we provide evidence of cell-to-cell interaction between rat germ cells and Leydig or Sertoli cells in relation to nitric oxide (NO) pro duction and inducible nitric oxide synthase (iNOS) messenger RNA (mRNA) exp ression. As a result of being cultured in a round spermatid-conditioned med ium (RSd-CM), NO production in both Leydig and Sertoli cells increased in p roportion to the length of the culture period, iNOS mRNA expression in both types of cells also increased in a dose-dependent manner as a result of be ing cultured with RSd-CM. This increase was detected as early as 3 h and wa s maintained up to 24 h. In contrast, neither NO production nor iNOS mRNA i ncreased in either type of cell following culture in a pachytene spermatocy te-conditioned medium (PS-CM). Our findings suggest that RSd may control NO production of Leydig and Sertoli cells. This cell-to-cell interaction may be an important mechanism of regulation of testicular function. (C) 2000 El sevier Science Ireland Ltd. All rights reserved.