Effect of [4Cl-D-Phe6,Leu17]VIP on the inhibition of pulsatile LH release by VIP and related peptides in the ovariectomized rat.
Pulsatile LH secretion in the ovariectomized (OVX) rat is inhibited by intracerebroventricular (icv) infusion of vasoactive intestinal peptide (VIP). VIP, rat growth hormone-releasing hormone (rGRH) and secretin with and without an antagonist to VIP, [4Cl-D-Phe6,Leu17]VIP (VIPA), were infused icv into OVX rats. Both VIP and rGRH at an infusion rate of 3.5 nmol/h lowered mean LH concentrations and pulse frequency without affecting pulse amplitude, and these effects were blocked by concurrent infusion of VIPA (10.5 nmol/h). Secretin also inhibited pulsatile LH secretion, but was only fully effective at the higher infusion rate of 7 nmol/h. This effect of secretin was also blocked by concurrent infusion of 10.5 nmol/h of VIPA. These results suggest that all three of these peptide hormones inhibit pulsatile LH secretion by an interaction with VIP receptors.
Weick
R F
RF
Department of Physiology, University of Western Ontario, London, Canada.
Stobie
K M
KM
Noh
K A
KA
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D013007:Growth Hormone-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology; D007276:Injections, Intraventricular; D007986:Luteinizing Hormone / Q000378:metabolism*; D010052:Ovariectomy; D010507:Periodicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012633:Secretin / Q000008:administration & dosage / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*
C048507:vasoactive intestinal peptide, 4-chloro-Phe(6)-Leu(17)-; D012633:Secretin; D014660:Vasoactive Intestinal Peptide; D007986:Luteinizing Hormone; D013007:Growth Hormone-Releasing Hormone