The Metopirone test of pituitary corticotrophin release: Evaluation of 101 tests

Abstract

The ACTH secreting potential of the pituitary gland was tested, using the steroidal 11β-hydroxylase inhibitor, Metopirone ®, in eighty patients (1 gm. Metopirone orally each six hours for forty-eight hours) on 101 occasions, and the increase in 17-oxogenicsteroid (OGS) excretion was followed. Twenty-one patients had a maximum OGS response of less than 50 mg. Of these, fifteen had a history of hypopituitarism, pituitary damage or steroid suppression, and the remainder were either suffering from metastatic breast cancer or had been treated with tranquilizer drugs. All patients judged clinically to have a normal adrenal-pituitary axis had a response of between 50 and 100 mg. per day. Of the twenty-three patients who had an OGS response greater than 100 mg. per day, nine were suffering from Cushing's syndrome, four from acromegaly and five were obese. The effect of Metopirone on OGS excretion provides a clinically useful test of pituitary ACTH “reserve”. Metopirone caused increases in the excretion of 11-desoxy-OGS which were about half the OGS increases and which gave no better correlation with clinical status.