title: Stage-dependent regulation of ovarian pituitary adenylate cyclase-activating polypeptide mRNA levels by GnRH in cultured rat granulosa cells.
abstract: The present study was designed to test whether GnRH regulates pituitary adenylate cyclase-activating polypeptide mRNA levels in a stage-dependent manner during follicle development in the rat ovary. The granulosa cells of preovulatory and immature follicles obtained from PMSG- and estrogen-treated rats, respectively, were cultured in serum-free conditions in the presence of various hormones. GnRH receptor mRNA expression was detected in both preovulatory and immature granulosa cells and was down-regulated by gonadotropins. Treatment of preovulatory granulosa cells with GnRH agonist stimulated pituitary adenylate cyclase-activating polypeptide mRNA levels in a dose-dependent manner. In situ hybridization analysis of cultured preovulatory follicles revealed that GnRH-induced pituitary adenylate cyclase- activating polypeptide signals were detected in granulosa cells, but not thecal cells. In immature granulosa cells, cotreatment with GnRH agonist suppressed FSH-stimulated pituitary adenylate cyclase-activating polypeptide mRNA levels in a dose-dependent manner, whereas treatment with GnRH alone had no effect. Furthermore, treatment with GnRH antagonist inhibited LH-induced pituitary adenylate cyclase-activating polypeptide gene expression in preovulatory granulosa cells, whereas it stimulated FSH-induced pituitary adenylate cyclase-activating polypeptide gene expression in immature granulosa cells. Interestingly, GnRH-stimulated pituitary adenylate cyclase-activating polypeptide mRNA levels in preovulatory granulosa cells was inhibited by arachidonyltri fluoromethyl ketone, an inhibitor of phospholipase A(2), but not by an inhibitor of protein kinase A or C. Lastly, treatment of preovulatory follicles with pituitary adenylate cyclase-activating polypeptide antagonist suppressed GnRH-stimulated progesterone production during 6--9 h of culture. Taken together, these results demonstrate the stage-dependent regulation of pituitary adenylate cyclase-activating polypeptide mRNA levels by GnRH, the stimulatory and inhibitory effect in granulosa cells of preovulatory and immature follicles, respectively.
authors.affiliation: Hormone Research Center, Chonnam National University, Kwangju 500-757, Republic of Korea.
authors.forename: J Y
authors.initials: JY
authors.lastname: Park
authors.forename: J H
authors.initials: JH
authors.lastname: Park
authors.forename: H J
authors.initials: HJ
authors.lastname: Park
authors.forename: J Y
authors.initials: JY
authors.lastname: Lee
authors.forename: Y I
authors.initials: YI
authors.lastname: Lee
authors.forename: K
authors.initials: K
authors.lastname: Lee
authors.forename: S Y
authors.initials: SY
authors.lastname: Chun
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000502:physiology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D005498:Follicular Phase; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D006107:Granulosa Cells / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000494:pharmacology; D009479:Neuropeptides / Q000037:antagonists & inhibitors / Q000235:genetics*; D006080:Ovarian Follicle / Q000378:metabolism; D010053:Ovary / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011374:Progesterone / Q000096:biosynthesis; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D010741:Phospholipases A