To study the role of extracellular nucleosides and nucleotides in the regulation of Sertoli cells, the effects of agonists which occupy A 1 and P 2 purinergic receptors on aromatase and gamma-glutamyl transpeptidase ( -GTP) activities and on transferrin secretion were tested. Sertoli cell treatment with purinergic agonists for a prolonged period of time (72 h) resulted in an increase in aromatase activity under basal conditions. In cultures stimulated with FSH, purinergic agonists counteracted the inhibitory effect on aromatase activity that long-term treatment with FSH promoted. The effects of prolonged treatments with purinergic agonists on the other two parameters of Sertoli cell function were less pronounced. Neither -GTP activity nor transferrin secretion was modified under basal conditions. On the other hand, under conditions where cell differentiation was favored by FSH treatment, reductions in -GTP activity and transferrin secretion were usually observed. The results obtained in dbcAMPstimulated cultures suggested that A 1 agonists exert their regulatory function at the level of cAMP formation while P 2 agonists act at a more distal point. The fact that morphological changes induced by FSH were reversed by both types of agonists, while those induced by dbcAMP were only abrogated by P 2 agonists, supports this hypothesis. In summary, these results demonstrate that purinergic agonists may be important in the regulation of Sertoli cell function.

Sertoli cells are under the control of FSH and androgens and also respond to polypeptidic factors locally produced. Basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) have been proposed to belong to the large set of intratesticular regulators. The aim of the present investigation was to analyze the effects of bFGF and NGF on lactate production, g-glutamyl transpeptidase (g-GTP) and aromatase activities. Cultured Sertoli cells dose-dependently responded to bFGF by increasing lactate production and g-GTP activity under basal conditions. In FSH-stimulated cultures, a synergistic effect of FSH with bFGF for lactate production was observed. NGF did not produce changes in lactate production or g-GTP activity at any dose tested. Both peptides decreased FSH-stimulated aromatase activity.These results provide additional evidence for the participation of bFGF and NGF in the complex network of intratesticular regulators. bFGF has pleiotropic effects on Sertoli cell function while the actions of NGF seem to be more limited.