Luteotropic effects of follicle-stimulating hormone (FSH): I. FSH has in vitro luteotropic and synergistic effects with luteinizing hormone and prolactin on progesterone production by hamster luteal cells during pregnancy.

This study was designed to evaluate the in vitro ability of FSH, LH, and prolactin (PRL) to stimulate progesterone (P4) production by enzymatically dispersed CL cells from pregnant hamsters. In light of previous in vivo findings [1], we were especially interested in determining whether FSH is a luteotropin. The CL were collected and pooled on Days 4, 8, 12, and 16 of gestation (Day 1 = sperm-positive vaginal smear). After enzymatic dissociation, combined large and small luteal cells (LC+SC) were incubated in the presence of 10 ng ovine (o) FSH, oLH, and oPRL, alone or in various combinations, for a total of 144 h with the first medium change at 24 h and other changes every 48 h thereafter. FSH and LH alone significantly increased P4 production on Days 4, 8, and 12, while PRL alone increased P4 only on Day 12 (p < 0.05). The combination oFSH+oLH+oPRL significantly stimulated P4 production on Day 4 to a greater extent than the combination of any two hormones (p < 0.05). Ovine FSH+oLH enhanced P4 production on Days 12 and 16 at 48, 96, and 144 h of incubation, to an extent greater than either hormone alone (p < 0.05). When recombinant human FSH (r-hFSH), which is devoid of LH activity, was added (1-100 ng) to dispersed luteal cells from Day 4 pregnant hamsters, a dose-response increase in P4 was evident (p < 0.05); even 1 ng r-hFSH stimulated P4 production at 96 h (p < 0.05). On Day 2 of the cycle, oFSH or oLH, but not oPRL, also significantly stimulated P4 production (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)