Altered pituitary hormone response to naloxone in hypertension development

Endogenous opioid regulation of blood pressure is altered during stress in young adults at risk for hypertension. We studied the effects of the opioid antagonist naloxone on the secretion of corticotropin and /3-endorphin during psychological stress in young adults with mildly elevated casual arterial pressures. Naloxone-induced secretion of both corticotropin and 0-endorphin was significantly diminished in persons at enhanced risk for hypertension compared with the low blood pressure control group. Results suggest that opioidergic inhibition of anterior pituitary function is altered in hypertension development. {Hypertension 1989;14:636-644) Endogenous opioids interact with circulatorycontrol nuclei at several distinct anatomicsites, including adrenal medullae and periph-eral sympathetic ganglia,1-2 nucleus tractus soli-tarius,3 and hypothalamic paraventricular nuclei.4-5 This multiplicity of pathways results in pressor or depressor actions of opioid antagonists, depending on the dose, site of action, behavioral state, and the species under investigation.6-8 Recent work with the stereospecific opioid antagonist naloxone sug