A comparison of the actions of stimulatory follicular fluid and gonadotropin-releasing hormone analogs on progesterone secretion by porcine granulosa cells.
Granulosa cells from small and medium porcine follicles (1-5 mm) were incubated with charcoal-treated follicular fluid from large (6-10 mm) follicles or porcine serum in the presence and absence of gonadotropin-releasing hormone (GnRH) analog and luteinizing hormone (LH) or follicle-stimulating hormone (FSH). A GnRH agonist inhibited follicular fluid's enhancement of basal and LH-stimulated progesterone secretion but did not block follicular fluid's enhancement of FSH-stimulated progesterone secretion. A GnRH antagonist mimicked follicular fluid's enhancement of basal and LH-stimulated progesterone secretion but did not mimic follicular fluid's action on FSH-stimulated progesterone secretion. When the GnRH antagonist and follicular fluid were added together, they acted synergistically in stimulating basal progesterone secretion, and were additive in enhancing LH-stimulated progesterone secretion. These observations suggest that separate follicular fluid molecules are responsible for its influence on LH and FSH actions on granulosa cells and that a GnRH-antagonist-like molecule could be responsible for some of follicular fluid's "luteinization stimulatory" action. Alternatively, the stimulatory follicular fluid molecule may not resemble GnRH but may act via a mechanism that is opposed by GnRH.
Ledwitz-Rigby
F
F
Department of Biological Sciences, Northern Illinois University, Dekalb 60115.
D000818:Animals; D002478:Cells, Cultured; D005260:Female; D015571:Follicular Fluid / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects* / Q000378:metabolism; D010906:Pituitary Hormone-Releasing Hormones / Q000037:antagonists & inhibitors; D011374:Progesterone / Q000378:metabolism*; D013552:Swine
D010906:Pituitary Hormone-Releasing Hormones; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; C063018:LHRH, Ac-dehydro-Phe(1)-dehydro-4-Cl-Phe(2)-dehydro-Trp(3,6)-