PACAP participates in the regulation of the hormonal events preceeding the ovulation.
Pituitary adenylate cyclase activating polypeptide (PACAP) is a member of the secretin family. It was isolated and characterized in 1989. Its neuroendocrine role was demonstrated in vivo and in vitro systems. It seems that in vivo the effect of PACAP on the gonadotrop hormone secretion depends on the route of administration. It was reported that intravenous (i.v.) injection of PACAP elevated, while intra-cerebro-ventricular (i.c.v.) administration depressed plasma LH levels. In the present study it was demonstrated that PACAP, administered i.c.v. before the critical period of the proestrous stage, blocked the ovulation and prevented the proestrous LH surge in rats. The blocking effect of PACAP is not directly mediated by endogenous opioids because the antagonizing effect of Naloxone, an opioid receptor antagonist, was questionable. Under our experimental conditions we could not confirm the stimulating effect of i.v. administered PACAP.
Köves
K
K
Department of Humanmorphology and Developmental Biology, Semmelweis University Medical School, Budapest, Hungary.
Molnár
J
J
Kántor
O
O
Lakatos
A
A
Görcs
T J
TJ
Somogyvári-Vigh
A
A
Fürst
Z
Z
Arimura
A
A
D000818:Animals; D005260:Female; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D009270:Naloxone / Q000008:administration & dosage; D009292:Narcotic Antagonists; D009479:Neuropeptides / Q000008:administration & dosage / Q000502:physiology*; D010060:Ovulation / Q000187:drug effects / Q000502:physiology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000502:physiology; D011359:Proestrus / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
C495403:Adcyap1 protein, rat; D009292:Narcotic Antagonists; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D009270:Naloxone; D007986:Luteinizing Hormone