Stimulation of ACTH secretion by indomethacin and reversal by exogenous prostaglandins.

The prostaglandin (PG) synthesis inhibitor, indomethacin, has been found to enhance adrenocorticotropin (ACTH) secretion upon injection directly into the anterior pituitary at a dose that is ineffective intravenously. Such stimulation was observed in combination with, and in the absence of, stimulation by a corticotropin-releasing factor (CRF) preparation. It was reversed to varying degrees by replacing certain PGs exogenously. It suggested that endogenous PGs in the anterior pituitary participate in the modulation of the sensitivity of this gland to the hypothalamic neurohormone, CRF.