Evidence for noradrenergic involvement in naloxone-induced stimulation of luteinizing hormone release in prepubertal female rats.

The effects of phenoxybenzamine an alpha-adrenergic blocker, propranolol a beta-adrenergic blocker, and diethyldithiocarbamate a noradrenaline synthesis inhibitor, on the LH increase induced by naloxone an opiate antagonist, was investigated in 25 day old female rats. Pretreatment with phenoxybenzamine or diethyldithiocarbamate suppressed the LH increase induced by naloxone, whereas pretreatment with propranolol had no significant effects on the naloxone-induced LH release. These results suggest that naloxone-induced increase in LH release is mediated via a noradrenergic mechanism.