Changes in pituitary secretion induced by an agonist-antagonist opioid drug, buprenorphine.

The im administration in 6 healthy subjects of buprenorphine, a derivative of the morphine alkaloid thebaine with agonist-antagonist properties, resulted in a significant rise of serum Prl within 45-240 min, a small and transient increase in serum GH and a significant fall in serum cortisol values. Conversely, no appreciable changes in the serum levels of the other hormones studied were found. The observed hormonal effects indicate that, in man, buprenorphine exerts an opiate agonist rather than an opiate antagonist effect.