Influence of low doses of naloxone on pituitary secretion in man

Naloxone 0.8 mg im administered to eight healthy subjects did not affect the serum levels of GH, LH, FSH, PRL, TSH and cortisol. Pretreatment with naloxone 0.8 mg increased TRH-induced TSH and PRL release in six healthy subjects. The same pretreatment caused an enhancement of haloperidol-induced PRL secretion in further other group of six subjects.