Effect of prolactin on follicle-stimulating hormone receptor binding and progesterone production in cultured porcine granulosa cells

Objective: To determine the effect of prolactin (PRL) on follicle-stimulati ng hormone receptor (FSH-R) binding and progesterone (P) production in cult ured porcine granulosa cells. Design: Controlled experiment. Setting: Academic research laboratory. Intervention(s): Immature granulosa cells were cultured in a serum-free med ium. All cell populations were supplemented with porcine (p) FSH and cultur ed in the absence or presence of ovine to PRL. Main Outcome Measure(s): Specific pFSH-R binding and P in medium. Result(s): In the control cells, FSH-R binding increased 31-fold and P prod uction increased 700-fold by day 4. Physiologic levels of oPRL potentiated the action of pFSH and resulted in a further 50% increase in pFSH-R binding and P production by day 4 over that in controls. In contrast, higher conce ntrations of oPRL blocked the rise in both pFSH-R binding and P production. The alteration in pFSH-R binding was associated with a change in FSH-R num ber. Conclusion(s): Physiologic levels of PRL amplify the stimulatory effects of FSH on the acquisition of the FSH-R and P production in cultured granulosa cells. Higher concentrations of PRL cause a decrease in FSH-R binding and P production. Prolactin may act as a "co-gonadotropin" and fine-tune the pr ocess of folliculogenesis by altering the acquisition of granulosa FSH rece ptors. Fertil Steril(R) 2000;73:99-105. (C)1999 by American Society for Rep roductive Medicine.