Fourteen patients with pituitary lesions and 6 normal subjects underwent the following tests: a) LHRH (100 mcg) + TRH (200 mcg) + Human Insulin (0.1 UI/kg) i.v. (Politest "A"); b) LHRH (100 mcg) + TRH (200 mcg) + GHRH 1-29NH2 (100 mcg) i.v. (Politest "B"); c) GHRH 1-29NH2 (100 mcg) i.v. (GHRH-TEST). FSH, LH and PRL, as assayed in patients and controls in response to Politest "A" and "B", revealed no significant differences between the tests. Plasma TSH values were significantly higher after Politest "B" in both patients and normals. The GH response after Politest "A" and "B" was similar in magnitude and concordant in 88.8% of cases.