Gonadotropin regulation of rat ovarian lysosomes: existence of a hormone specific dual control mechanism.

Gonadotropic hormones PMSG (15 IU/rat), FSH (3 micrograms/rat), LH (9 micrograms/rat) and hCG (3 micrograms/rat) were shown to decrease the free cytosolic lysosomal enzymes during the acute phase of hormone action in rat ovaries. When isolated cells from such rats were analyzed for the cathepsin-D activity, the granulosa cells of the ovary showed a reduction in the free as well as in the total lysosomal enzyme activities in response to FSH/PMSG; the stromal and thecal compartment of the ovary showed a reduction only in the free activity in response to hCG/PMSG. The results suggest the presence of two distinct, target cell specific, mechanisms by which the lysosomal activity of the ovary is regulated by gonadotropins.