Induction of maturation in follicle-enclosed oocytes: the response to gonadotropins at different stages of follicular development

• Published in: Biology of reproduction Vol. 38; no. 3; pp. 517 - 521
• Main Authors: DEKEL, N, GALIANI, D, BEERS, W. H
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01.04.1988
• Subjects: Adenylyl Cyclases - physiology; Animals; Biological and medical sciences; Colforsin - pharmacology; Cyclic AMP - analysis; Cyclic AMP - physiology; Diterpenes - pharmacology; Female; Follicle Stimulating Hormone - pharmacology; Follicular Phase - drug effects; Fundamental and applied biological sciences. Psychology; Granulosa Cells - analysis; Granulosa Cells - drug effects; Hormone metabolism and regulation; Luteinizing Hormone - pharmacology; Mammalian female genital system; Oogenesis - drug effects; Ovarian Follicle - analysis; Ovarian Follicle - drug effects; Pregnancy; Rats; Rats, Inbred Strains; Receptors, Gonadotropin - physiology; Vertebrates: reproduction; Theca folliculi; Ovulation inducer; Rat; Rodentia; Cyclic AMP; Gonadotropin; Glycoprotein hormone; In vitro; Ovary; Vertebrata; Pituitary hormone; Mammalia; Sensitivity resistance; Female genital system; Forskolin; FSH; Developmental stage; Granulosa; LH; Ovarian follicle; Oocyte maturation
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod38.3.517

Antral follicles, isolated from either nontreated or pregnant mare's serum gonadotropin (PMSG)-primed 27-day-old rats, were incubated in the absence or the presence of either luteinizing hormone (LH), follicle-stimulating hormone (FSH), or forskolin. The effect of these agents on oocyte maturation and cyclic adenosine 3',5'-monophosphate (cAMP) accumulation was studied and compared. Both gonadotropins, LH and FSH, as well as forskolin, effectively induced maturation of oocytes enclosed by large antral follicles isolated from PMSG-primed rats. On the other hand, we found that maturation of oocytes enclosed by small antral follicles, isolated from nonprimed and PMSG-primed rats, could be induced by either FSH or forskolin but not by LH. cAMP determinations revealed that, in spite of the inability of LH to induce oocyte maturation, elevated concentrations of the nucleotide were detectable in small antral follicles exposed to this gonadotropin. Since granulosa cells isolated from the large but not the small antral follicles were stimulated by LH to generate cAMP, the elevation of cAMP concentrations in the small antral follicle apparently represented the response of the theca cells to this gonadotropin. Since it is the ability of the granulosa cells to interact with the hormone that determines whether or not oocyte maturation will occur, we suggest that the granulosa, but not the theca cells, mediate LH action to induce oocyte maturation.