PROGESTERONE PRODUCTION IN-VITRO BY MOUSE LUTEAL CELLS - RESPONSE TO FOLLICLE-STIMULATING-HORMONE, LUTEINIZING-HORMONE, AND PROLACTIN

The purpose of this study was to determine the effects of ovine follic le-stimulating hormone (FSH), luteinizing hormone (LH); prolactin, and recombinant FSH and a protein kinase C activator (phorbol 12-myristat e 13-acetate [PMA]) on progesterone production by dispersed luteal cel ls (large + small) from Day 4 pregnant mice. Corpora lutea (CL) were c ollected on Day 4 of pregnancy (Day 1 = sperm positive smear), and dis persed luteal cells were isolated using collagenase. After overnight i ncubation, the luteal cells were incubated with or without FSH, LH, pr olactin, or recombinant human FSH or PMA for 4 hr or an additional 24 hr at 37 degrees C; media were collected and progesterone was determin ed by RIA. Ten nanograms and 100 ng of ovine FSH, LH and prolactin wer e all equally effective in stimulating progesterone synthesis in media recovered after 24 hr of incubation. Moreover, the combination of all three gonadotropins yielded maximum levels of progesterone indicating a luteotrophic complex in vitro, paralleling previous in vivo finding s. Recombinant human FSH-devoid of LH contamination-at doses of 10 and 100 ng also significantly stimulated progesterone synthesis, which st rongly suggests that FSH has luteotropic activity in the mouse, thus a greeing with our previous in vitro results with CL of the pregnant ham ster and rat. One hundred nanomolar PMA by itself did not affect proge sterone production but significantly decreased dibutyrl cAMP-, forskol in-, FSH-, and LH-induced progesterone production, suggesting that act ivation of protein kinase C may block the luteotropic effects of LH an d FSH during murine pregnancy.