Influence of testosterone on protein/peptide secretion as characterized by the formation of granular vesicles in rat and mouse pinealocytes. An in vitro study.

In the present study, using an in vitro system, the effect of testosterone on protein/peptide secretion in mouse and rat pinealocytes as characterized by the formation of granular vesicles (GV) has been studied. In both species testosterone induces a significant increase in the number of GV. This effect, however, is observed only when the pineals are cultured in a noradrenaline-free medium. These results clearly demonstrate that testosterone, at least under these in vitro conditions, is involved in the regulation of protein/peptide secretion, and point to the importance of pineal proteic/peptidic "hormones" in pineal endocrinology.