Cell-cell communication in the testis.

In addition to the well-established endocrine regulation of testicular functions by gonadotropins, many data accumulated in the last few years indicate that a local control is required for a normal production of androgens and spermatogenesis. In the present paper we review the cell-cell interactions between somatic and germ cells in the testis and their role on the function of each cell type. Also, we will present evidences indicating that some of these interactions are mediated by several growth factors produced and acting within the testis. Moreover, very often the production of these factors are under control of gonadotropins, and in turn the growth factors regulate the sensitivity of testicular cells to these hormones.