Pregnant mare serum gonadotrophin and follicle-stimulating hormone stimulation of cyclic AMP production in rat seminiferous tubule cells.

Pregnant mare serum gonadotrophin (PMSG) was found to stimulate the production of cyclic AMP in isolated rat seminiferous tubule cells. The PMSG was equipotent with highly purified ovine FSH. The subunits of PMSG were inactive in this system but recombination resulted in partial restoration of activity, and the combination of PMSG alpha-subunit with FSH beta-subunit was even more active. Desialation of PMSG, but not of ovine FSH, resulted in a reduction of slope and potency of this response, suggesting that sialic acid may be important for the interaction of PMSG and the Sertoli cell. Further tests of the responsiveness of this cell preparation demonstrated activity with several species of mammalian FSH molecules, but not with FSH molecules obtained from non-mammalian species.