Effects of selective histamine H3-receptor ligands on prolactin and growth hormone secretion in the rat.
The effects of intracarotid (i.a.) administration of the histamine (HA) H3-receptor agonist (R)-alpha-methyl-histamine (alpha MeHA) and of the H3-antagonist thioperamide, (THIO) on basal or morphine (M)-induced prolactin (PRL) and growth hormone (GH) secretion were studied in male rats. M was administered 3 h after the H3-drugs. Neither THIO (2.5 mg/kg) nor alpha MeHA (10 mg/kg) changed basal PRL levels and only THIO enhanced the PRL-releasing effect of M (6 mg/kg). Basal GH secretion was not modified by THIO. alpha MeHA slightly increased GH secretion. THIO significantly decreased M-stimulated GH secretion (1 mg/kg, i.a.) and alpha MeHA slightly increased it. These results, in agreement with previous evidence obtained after central HA administration, indicated that endogenous brain HA facilitates PRL and inhibits GH secretion.
Netti
C
C
Department of Pharmacology, Chemotherapy and Medical Toxicology, University of Milan, Italy.
Guidobono
F
F
Sibilia
V
V
Pagani
F
F
Villa
I
I
Pecile
A
A
D000818:Animals; D013006:Growth Hormone / Q000378:metabolism*; D006633:Histamine Antagonists; D007700:Kinetics; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology*; D009020:Morphine / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011968:Receptors, Histamine / Q000502:physiology*; D018100:Receptors, Histamine H3
D006633:Histamine Antagonists; D008761:Methylhistamines; D010880:Piperidines; D011968:Receptors, Histamine; D018100:Receptors, Histamine H3; C069357:alpha-methylhistamine; D009020:Morphine; D011388:Prolactin; D013006:Growth Hormone; C052075:thioperamide