Effects of acute and chronic haloperidol treatment on the concentrations of immunoreactive beta-endorphin in plasma, pituitary and brain of rats.
Haloperidol (0.03-3 mg/kg) dose-dependently increased the plasma concentrations of immunoreactive beta-endorphin (ir-beta-END) without changing the concentrations of ir-beta-END in the adenohypophysis or the neurointermediate pituitary of rats. Elevated levels of ir-beta-END in plasma were also found after chronic treatment with haloperidol (1 mg/kg per day) for 3 weeks. The long-term treatment, however, caused a selective increase (60%) of the ir-beta-END concentrations in the neurointermediate pituitary without changing that in the adenohypophysis. Significantly elevated levels of ir-beta-END were also found in the hypothalamus and the septum. Gelchromatographic separation of the plasma components reacting with the beta-endorphin antiserum revealed that both the acute and chronic haloperidol treatment increased the plasma concentrations of immunoreactive material with the molecular size of beta-endorphin and beta-lipotropin. This indicates that, at least, part of ir-beta-END released by haloperidol into plasma is of adenohypophyseal origin, since no material with the molecular size of beta-lipotropin has been found in the neurointermediate pituitary.
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002850:Chromatography, Gel; D004723:Endorphins / Q000097:blood / Q000378:metabolism*; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D001615:beta-Endorphin
D004723:Endorphins; D001615:beta-Endorphin; D006220:Haloperidol