Hypophyseal hormone levels in blood and cerebrospinal fluid in response to histamine and pentylenetetrazol.
Histamine administered intraperitoneally increased, in a dose-dependent manner, AVP, OXT and PRL levels in plasma of rats, whereas alpha-MSH levels were not affected. Levels of AVP in plasma after histamine 20.0 mg/kg treatment were approximately 100-fold higher than those of controls, while OXT and PRL levels were approximately 7-fold higher after this treatment. CSF content of AVP, OXT, PRL and alpha-MSH was not influenced by histamine, indicating that a stimulated release of hormones from the pituitary into the blood is not accompanied by a concomitant increase of secretion of these hormones into the CSF. Convulsions induced by pentylenetetrazol were accompanied by a temporary increase in AVP levels and by strongly and consistently elevated OXT levels in plasma. PRL and alpha-MSH plasma levels were affected in a biphasic manner. A convulsion type 1 induced elevated PRL levels and diminished alpha-MSH levels, while a convulsion type 2 had no effect on plasma PRL concentration, but increased the concentration of alpha-MSH. Only the level of OXT in CSF was increased after a pentylenetetrazol-induced convulsion type 1. The present data suggest that histamine affects the release of AVP, while pentylenetetrazol might act more specifically on the OXT-releasing system. Furthermore, a possible relationship between the pentylenetetrazol-induced increase of OXT levels in the CSF and amnesia is suggested.
D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism; D006632:Histamine / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism; D010121:Oxytocin / Q000378:metabolism; D010433:Pentylenetetrazole / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects; D010907:Pituitary Hormones / Q000097:blood* / Q000134:cerebrospinal fluid*; D011388:Prolactin / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000378:metabolism
D010907:Pituitary Hormones; D001127:Arginine Vasopressin; D010121:Oxytocin; D006632:Histamine; D011388:Prolactin; D009074:Melanocyte-Stimulating Hormones; D010433:Pentylenetetrazole