transduction processes in Sertoli cells

Sertoli cells play a pivotal role in regulation and maintenance of spermato-genesis. They are hormonally regulated predominantly by follicle-stimulat-ing hormone (FSH) and testosterone (T). Although FSH and T have distinct mechanisms of action they act synergistically in promoting spermatogenesis. Stimulation of freshly isolated Sertoli cells with FSH evokes a prompt rise in cytosolic calcium which is quantitatively reproduced by cAMP. The cytosolic calcium response to FSH in Sertoli cells is mainly attributable to serial signaling after the generation of endogenous cAMP. Calcium homeostasis of Sertoli cells may also be regulated by cAMP-independent metabolism. Vasoactive testicular paracrine hormones such as angiotensin II (AII) and vasopressin acting via inositol triphosphate generation induce cytosolic calcium rise primarily derived from the thapsigargin-sensitive en-doplasmic reticulum. Investigations involving androgens action on cytosolic calcium reveal a common mechanism of action between the peptide and steroid regulators of Sertoli cell function, indicating that cytosolic calcium Cytosolic calcium and hormones in Sertoli cells220 ions may represent a unifying biochemical mechanism that could explain the synergism of FSH and T. Androgens rapidly and specifically increase cytosolic calcium, consistent with a plasma membrane site of action. This argues for the possible existence of a short term non-genomic signaling pathway in hormonal regulation of Sertoli cell function in addition to the classical longer term, slower genomic response. Reproductive Biology 200