[TGF beta (transforming growth factor beta) and its related peptides in the local control of the testicle].

Recent data on TGF beta (and related peptides) expression and action in the testis are briefly reviewed. At least, three isoforms of TGF beta are expressed during the male gonadal development. TGF betas are expressed in somatic and germ cells. The expression of the different isoforms varies during gonadal development and is cell specific. Both types I, II and III TGF beta receptors have been localized in somatic cells. TGF beta inhibits gonadotropin action both in Sertoli cells and Leydig cells as well as proliferation of germ cells and Leydig cells. Inhibins and activins (in terms of mRNA and proteins) are expressed in somatic cells and germ cells. Inhibin production in Sertoli cells is under the control of FSH, local factors (ex: EGF, insulin, opiods) and probably of germ cells. Activins and inhibins regulate Leydig and Sertoli cells activities and germ cells development. The existence of activin receptors in somatic and germ cells has been suggested by the presence of type II receptor mRNA (ActRII and ActRIIB).