Plasma LH, FSH and TSH responses to the synthetic enkephalin analog (FK 33-824) in normal subjects and patients with pituitary diseases.

D-Ala, Mephe, Met, enkephalin (Sandoz FK 33-824), 1.0 or 0.5 mg, was administered by i.v. infusion to normal subjects, patients with acromegaly and hyperprolactinemia due to pituitary adenoma and patients with pituitary dwarfism. FK 33-824 induced no significant change in plasma level of LH, FSH or TSH in any of the subjects studied. These results suggest a lesser role of opioid regulation in the release of above pituitary hormones compared with that in GH, PRL and cortisol.