Cocaine induced secretion of ACTH, beta-endorphin, and corticosterone

The effect of intraperitoneal administration of cocaine on the concentrations of hypothalamic corticotropin releasing factor like-immunoreactivity (CRF-LI), plasma ACTH, beta-endorphin, and corticosterone was investigated. Groups of rats were injected with 20 mg/kg cocaine HCI or 0.9% NaCl and then killed 0, 10, 20, 30 or 60 minutes later. Hypothalamic CRF-LI, plasma ACTH, beta-endorphin, and corticosterone concentrations were determined by radioimmunoassay. A significant increase in plasma ACTH, beta-endorphin, and corticosterone concentrations was observed after cocaine administration. In contrast, cocaine had no significant effect on hypothalamic CRF-LI concentrations. Intravenous administration of 0.5 and 2.0 mg/kg cocaine to rats in which the endogenous release of CRF was blocked by chlorpromazine, morphine, and pentobarbital elicited a significant increase in plasma corticosterone concentrations. These results demonstrate that cocaine induces the release of ACTH, beta-endorphin, and corticosterone and suggest that this response is mediated at the pituitary level.