FSH and LH stimulation of ornithine decarboxylase activity: studies with porcine granulosa cells in vitro.

Under defined conditions in vitro FSH and LH caused a dose-dependent stimulation of ornithine decarboxylase (ODC) activity in granulosa cells isolated from porcine ovarian follicles. In cells from small follicles, FSH was at least twice as potent an inducer of the enzyme activity as LH. The cells from medium-sized follicles were more responsive to both hormones than cells from small follicles. In addition, the cells from medium-sized follicles were approximately equally responsive to maximal FSH and LH stimulation. Incubation of cells from either small follicles or medium-sized follicles with maximum effective doses of LH plus FSH caused no additive effects.