Title: Tetrachlorodibenzo-p-dioxin alters rat hypothalamic endorphin and mu opioid receptors.

Authors: Bestervelt, L L; Nolan, C J; Cai, Y; Maimansomsuk, P; Mousigian, C A; Piper, W N

Published In Neurotoxicol Teratol, (1991 Sep-Oct)

Abstract: The present study was undertaken to assess if hypothalamic beta-endorphin (beta E) and/or brain mu opioid receptors are associated with 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) (50 micrograms/kg)-induced hypophagia and body weight decline in rats. Hypothalamic beta E concentrations were initially increased to 166% of controls on day 1, and then were depressed to 39% and 49% of control values on days 2 and 3, respectively. Brain mu opioid receptor number was increased 60% in TCDD-treated rats at day 3 without a change in the binding affinity. Food-restricted rats did not exhibit changes in hypothalamic beta E concentrations or brain mu opioid receptor number. These results indicate that TCDD causes early perturbations in hypothalamic beta E concentrations and brain mu receptor number, which may contribute to the mechanisms by which TCDD leads to decreased food intake and progressive weight loss.

PubMed ID: 1661835

MeSH Terms: Animals; Brain/drug effects; Brain/metabolism*; Cell Membrane/metabolism; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Enkephalins/metabolism; Food Deprivation; Hypothalamus/drug effects; Hypothalamus/metabolism*; Kinetics; Male; Polychlorinated Dibenzodioxins/pharmacology*; Rats; Rats, Inbred Strains; Receptors, Opioid, mu; Receptors, Opioid/drug effects; Receptors, Opioid/metabolism*; Reference Values