Preoptic injection of VIP, but not of secretin or PHI, inhibits LH and stimulates prolactin secretion in the ovariectomized rat.
The microinjection of vasoactive intestinal peptide (VIP) into the medial preoptic area rapidly inhibited pulsatile luteinizing hormone (LH) secretion within 1 h in ovariectomized rats. A transient but significant increase in prolactin (PRL) secretion occurred after VIP injection coincidentally with the initiation of the inhibition of LH pulses. Preoptic microinjections of secretin or peptide histidine isoleucine amide (PHI) did not have such effects. These results suggest specific actions of VIP, despite its structural similarity to secretin and PHI, on the preoptic mechanisms governing LH and PRL secretion in ovariectomized rats.
Akema
T
T
Department of Physiology, Yokohama City University School of Medicine, Japan.
Hashimoto
R
R
Kimura
F
F
D000818:Animals; D005260:Female; D007700:Kinetics; D007986:Luteinizing Hormone / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010052:Ovariectomy; D010451:Peptide PHI / Q000494:pharmacology*; D011301:Preoptic Area / Q000187:drug effects / Q000502:physiology*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012633:Secretin / Q000494:pharmacology*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D010451:Peptide PHI; D012633:Secretin; D014660:Vasoactive Intestinal Peptide; D011388:Prolactin; D007986:Luteinizing Hormone