title: Histaminergic mediation of the stress-induced release of prolactin in male rats.
abstract: Histamine (HA) is likely to participate in the neuroendocrine regulation of prolactin (PRL) secretion. We, therefore, studied the possible involvement of HA in the stress-induced release of PRL in conscious male rats. HA (30 micrograms) infused intracerebroventricularly 15 min before decapitation elevated PRL plasma levels from 5 +/- 1 to 54 +/- 6 ng/ml (p less than 0.01). Intracerebroventricular infusion of the H2 receptor antagonists cimetidine (CIM: 100 micrograms) or ranitidine (RAN: 125 micrograms) abolished the PRL response to HA (p less than 0.01), while intracerebroventricular infusion of the H1 receptor antagonist mepyramine (MEP; 100 micrograms) inhibited the response only 40% (p less than 0.05). Intra-arterial infusion of CIM (2,000 micrograms) or RAN (2,500 micrograms) inhibited the HA-stimulated PRL secretion 52% (p less than 0.01) or 63% (p less than 0.01), respectively. The H1 receptor antagonists MEP (1,000 micrograms) and SKF-93944 (1,500 micrograms) had no effect following intra-arterial administration. Restraint stress increased the PRL level to 84 +/- 6 ng/ml (p less than 0.01 vs. control). This effect was prevented by intracerebroventricular infusion of CIM or RAN (p less than 0.01) and inhibited 75% by MEP (p less than 0.01). Intra-arterial infusion of CIM, MEP, and SKF-93944 inhibited the stress response about 50% (p less than 0.01), while RAN decreased the response only 25% (p less than 0.05). Ether stress elevated the plasma PRL concentration to 46 +/- 5 ng/ml (p less than 0.01 vs. control). When infused intracerebroventricularly CIM or RAN prevented the response (p less than 0.01), while MEP had no effect.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medical Physiology C, Panum Institute, University of Copenhagen, Denmark.
authors.forename: U
authors.initials: U
authors.lastname: Knigge
authors.forename: S
authors.initials: S
authors.lastname: Matzen
authors.forename: J
authors.initials: J
authors.lastname: Warberg
mesh_terms: D000818:Animals; D002927:Cimetidine / Q000008:administration & dosage / Q000494:pharmacology; D004986:Ether; D006632:Histamine / Q000008:administration & dosage / Q000502:physiology*; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D008297:Male; D011388:Prolactin / Q000097:blood*; D011738:Pyrilamine / Q000008:administration & dosage / Q000494:pharmacology; D011744:Pyrimidinones / Q000008:administration & dosage / Q000494:pharmacology; D011899:Ranitidine / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011968:Receptors, Histamine / Q000187:drug effects; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000378:metabolism*
chemical_list: D011744:Pyrimidinones; D011968:Receptors, Histamine; D004986:Ether; D002927:Cimetidine; D006632:Histamine; D011899:Ranitidine; D011388:Prolactin; C049054:temelastine; D011738:Pyrilamine