Effect of nivazol on ACTH secretion by human pituitary corticotrophic tumours in cell culture.

The effects of nivazol, a novel steroid which lacks glucocorticoid activity, on ACTH secretion by cell cultures of human pituitary corticotrophic tumours has been investigated. Nivazol (0.002-20 mumol/l) inhibited ACTH secretion by 50-80%, after 4 and 24 h of incubation. (Trilostane (0.3-30 mumol/l) did not affect basal or stimulated ACTH secretion.) The potency of nivazol was comparable with that of hydrocortisone, and less than dexamethasone. The stimulatory effects of oCRF and AVP were reduced or completely blocked by nivazol in a similar manner to that previously described for hydrocortisone. It is concluded that nivazol may be of benefit in the direct treatment of Cushing's disease, particularly since it lacks glucocorticoid activity.