GnRH-induced PACAP and PAC1 receptor expression in pituitary gonadotrophs: a possible role in the regulation of gonadotropin subunit gene expression.
We examined the expression of pituitary adenylate cyclase-activating polypeptide (PACAP) and the PACAP type 1 receptor (PAC1-R) mRNA following gonadotropin-releasing hormone (GnRH) stimulation using the gonadotroph cell line LbetaT2. GnRH stimulation increased PACAP and PAC1-R mRNA expression in a static culture. Increase in the cell surface density of the PAC1-R following transfection with PAC1-R expression vectors significantly increased gonadotropin LHbeta and FSHbeta subunit promoter activities following 100 nM PACAP stimulation. In addition, increasing concentrations of PACAP stimulation augmented the promoter activities for both LHbeta and FSHbeta in PAC-1R overexpressing cells. In the cells with PAC1-R, the effect of GnRH was further potentiated in the presence of PACAP from 5.31+/-0.93 to 9.89+/-0.38-fold for LHbeta and for FSHbeta subunit, respectively; from 2.58+/-0.31-fold by GnRH alone to 10.90+/-2.79-fold with PACAP. The combination treatment with GnRH and PACAP did not augment the ERK phosphorylation induced by GnRH alone. PACAP expectedly increased cAMP accumulation and this effect was significantly attenuated in the presence of GnRH. PACAP gene expression was more prominent following lower frequency GnRH pulses (every 120 min) in a perifused culture. Our results suggest that PACAP and PAC1-R are produced locally within the gonadotrophs following GnRH stimulation. They subsequently affect the gonadotrophs in an autocrine manner and modulate the GnRH pulse-dependent specific regulation of gonadotropin subunits.
Purwana
Indri N
IN
Department of Obstetrics and Gynecology, Shimane University, School of Medicine, 89-1 Enya Cho, Izumo 693-8501, Shimane Prefecture, Japan.
Kanasaki
Haruhiko
H
Oride
Aki
A
Mijiddorj
Tselmeg
T
Shintani
Norihito
N
Hashimoto
Hitoshi
H
Baba
Akemichi
A
Miyazaki
Kohji
K
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D037201:Follicle Stimulating Hormone, beta Subunit; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D052681:Gonadotrophs / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D006065:Gonadotropins, Pituitary / Q000378:metabolism*; D037101:Luteinizing Hormone, beta Subunit; D051379:Mice; D010766:Phosphorylation; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D021122:Protein Subunits / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I / Q000235:genetics / Q000378:metabolism*; D013499:Surface Properties; D013997:Time Factors
C495402:Adcyap1 protein, mouse; C495504:Adcyap1r1 protein, mouse; D037201:Follicle Stimulating Hormone, beta Subunit; D006065:Gonadotropins, Pituitary; D037101:Luteinizing Hormone, beta Subunit; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D021122:Protein Subunits; D012333:RNA, Messenger; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D007987:Gonadotropin-Releasing Hormone; D000242:Cyclic AMP; D048049:Extracellular Signal-Regulated MAP Kinases