[The regulation of testicular function by paracrine mechanism]

It is well accepted that testicular function is controlled by gonadotropins. Androgen secretion is regulated by LH, whereas spermatogenesis is controlled by FSH and locally produced androgens. However, evidence has accumulated to indicate that this extratesticular control system is modulated by equally important intratesticular cell-cell interactions. The study of this local control system has received major impetus from the development techniques which have allowed isolation and culture of purified testicular cells and has revealed that testicular cells respond to previously unexpected variable humoral factors which are produced by testicular cells themselves, namely testicular paracrinology. Numerous reviews with regard to cell-cell interactions have been published. In this paper, we attempted to summarize recent topics of para and autocrinology of testicular androgen biosynthesis and spermatogenesis.