The Porcine Ovarian Follicle. VII. FSH Stimulation of in vitro [3H] -Glucosamine Incorporation into Mucopolysaccharides1

Abstract

Highly purified porcine follicle stimulating hormone (pFSH) stimulated the incorporation of [3H]-glucosamine into mucopolysaccharides of proteoglycans secreted by granulosa cells from porcine small (<2 mm) follicles. Stimulation by pFSH required at least 12 h of incubation, (Ax and Ryan, 1979b), was dose-dependent, and appeared to be specific for the hormone. Furthermore, the effect of pFSH showed a seasonal variation with maximal (3-fold) response during winter months, declining to a minimal (1.5-fold) response in August and September. Granulosa cells from large (>6 mm) follicles were less responsive to pFSH than were small follicle cells. The stimulatory effect of pFSH could be mimicked by dibutyryl cyclic AMP (dbcAMP) although the time course for dbcAMP stimulation was somewhat shorter than for pFSH. Prostaglandin E2 also increased the incorporation of [3H]-glucosamine into mucopolysaccharides and it enhanced the response to a maximally stimulating dose of pFSH. The response to FSH was inhibited by prolactin, dexamethasone, progesterone, and testosterone and by inhibitors of protein and RNA synthesis. Data presented here suggest that FSH stimulation of [3H]-glucosamine incorporation into mucopolysaccharides is mediated by cAMP and involves gene activation and/or synthesis of new protein. Hormonal regulation of proteoglycan synthesis would suggest an important role for these macromolecules in normal development of the ovarian follicle.