Cortisol response to arginine-vasopressin does not compare with cortisol response to insulin-hypoglycemia in pituitary tumors.
Timed cortisol responses to insulin-hypoglycemia (IH) and arginine-vasopressin (AVP) were compared in 16 patients with pituitary tumors and six healthy controls. Serum cortisol was estimated by a specific and sensitive radioimmunoassay as per the WHO protocol. The basal cortisol (AM) was normal (> 290 nmol/l) in 9 patients and low in seven. With IH peak cortisol response was normal (> 550 nmol/l) in 10 patients, 8 of whom had normal and 2 had low basal (AM) cortisol. In contrast AVP evoked normal cortisol responses in only 5 of these patients, all of whom had normal basal (AM) cortisol and none had low basal (AM) cortisol. The data indicate lower sensitivity for AVP stimulation test (50%) and favour IH as the standard cortisol stimulation test in patients with pituitary tumors awaiting surgery.
Lodha
S
S
Department of Endocrinology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Talwar
V
V
Bhansali
A
A
Dash
R J
RJ
D000293:Adolescent; D000328:Adult; D001127:Arginine Vasopressin; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007003:Hypoglycemia / Q000139:chemically induced*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D007328:Insulin; D008297:Male; D010911:Pituitary Neoplasms / Q000503:physiopathology*; D010912:Pituitary-Adrenal Function Tests; D010913:Pituitary-Adrenal System / Q000502:physiology
D007328:Insulin; D001127:Arginine Vasopressin; D006854:Hydrocortisone