Characterization of follicular fluid stimulatory factor upon FSH-induced granulosa cell differentiation.
The modulatory role of follicular fluid (FF) upon gonadotropin-induced granulosa cell (GC) differentiation has been previously demonstrated. In the present study, the stimulatory factor of large-antral FF (LFF) was partially characterized. Addition of ovine FSH to porcine GC culture increased 125I-hCG specific binding about 6-fold and progesterone (P4) secretion 15-fold. The FSH-induced 125I-hCG specific binding was increased 1.9-fold by LFF and decreased 7.7-fold in the presence of small-antral FF (SFF). It is suggested that SFF may contain an inhibitory factor which is overcome by a stimulatory factor accumulated in FF with follicular growth. An initial purification of LFF stimulatory factor was achieved by two-step ethanol elution. The obtained LFF purified fraction increased the FSH-induced 125I-hCG specific binding 1.5-fold and P4 secretion 4.3-fold compared to GC cultured with FSH + LFF. Addition of LH alone increased the P4 secretion 2.3-, 3.4-, and 6 fold in GC precultured with FSH alone, FSH + neat LFF, and FSH + LFF purified fraction, respectively, as compared to GC precultured in plain medium. Therefore, the LFF stimulatory increase of 125I-hCG specific binding may represent an increase of functional LH receptors. Freezing and thawing of LFF 4 times, exposing LFF to urea for 24 h, heating at 60 C for 20 min, and tryptic digestion each abolished the LFF stimulatory effect upon the FSH-dependent increase of 125I-hCG specific binding and P4 secretion. Thus, the LFF stimulatory activity could be attributed to one or more proteins.
Bar-Ami
S
S
Department of Physiology, University of Maryland School of Medicine, Baltimore 21201.
Channing
C P
CP
D000818:Animals; D001826:Body Fluids / Q000032:analysis / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D005615:Freezing; D006107:Granulosa Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D006358:Hot Temperature; D006080:Ovarian Follicle / Q000502:physiology*; D011374:Progesterone / Q000378:metabolism; D011506:Proteins / Q000494:pharmacology; D011974:Receptors, LH / Q000502:physiology; D012756:Sheep; D013552:Swine; D014357:Trypsin / Q000494:pharmacology
D006063:Chorionic Gonadotropin; D011506:Proteins; D011974:Receptors, LH; D011374:Progesterone; D005640:Follicle Stimulating Hormone; D014357:Trypsin