Neuronal glucoprivation enhances hypothalamic histamine turnover in rats.
Histamine (HA) turnover in the rat hypothalamus following insufficient energy supply due to glucoprivation was examined after administration of insulin or 2-deoxy-D-glucose (2-DG). HA turnover was assessed by accumulation of tele-methylhistamine (t-MH), a major metabolite of brain HA, following administration of pargyline. Intraperitoneal injection of 1, 2, and 4 U/kg of insulin, which had no influence on steady-state levels of HA and t-MH, increased pargyline-induced accumulation of t-MH. Accumulation of t-MH due to pargyline was inversely related to the concomitant plasma glucose concentration after different doses of insulin. The level of t-MH accumulated by pargyline did not change compared with that of controls, when a euglycemic condition was maintained or insulin at a dose of 6 mU per rat was infused into the third cerebroventricle. Intracerebroventricular infusion of 24 mumol per rat of 2-DG, which had no influence on steady-state levels of HA and t-MH, increased the level of t-MH enhanced by pargyline. The results indicate that an increase in hypothalamic HA turnover in response to glucoprivation may be involved in homeostatic regulation of energy metabolism in the brain.
Oohara
A
A
Department of Internal Medicine I, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Yoshimatsu
H
H
Kurokawa
M
M
Oishi
R
R
Saeki
K
K
Sakata
T
T
D000818:Animals; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D003847:Deoxyglucose / Q000008:administration & dosage / Q000494:pharmacology*; D006632:Histamine / Q000378:metabolism*; D007003:Hypoglycemia / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007263:Infusions, Parenteral; D007328:Insulin / Q000008:administration & dosage / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D008761:Methylhistamines / Q000378:metabolism; D010293:Pargyline / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D008761:Methylhistamines; D006632:Histamine; D003847:Deoxyglucose; D010293:Pargyline; C020404:tele-methylhistamine