Variable expression of the V1 vasopressin receptor modulates the phenotypic response of steroid-secreting adrenocortical tumors.

TLDR: It is concluded that the vasopressin V1 receptor gene is expressed in normal and tumoral adrenocortical cells and high, and not ectopic, expression occurs in a minority of tumors that become directly responsive to vasoppressin stimulation tests.

Abstract: We studied the putative role of the vasopressin receptors in the phenotypic response of steroid-secreting adrenocortical tumors. A retrospective analysis of a series of 26 adrenocortical tumors responsible for Cushing’s syndrome (19 adenomas and 7 carcinomas) showed that vasopressin (10 IU, im, lysine vasopressin) induced an ACTH-independent cortisol response (arbitrarily defined as a cortisol rise above baseline of 30 ng/mL or more) in 7 cases (27%). In comparison, 68 of 90 patients with Cushing’s disease (76%) had a positive cortisol response. We then prospectively examined the expression of vasopressin receptor genes in adrenocortical tumors of recently operated patients (20 adenomas and 19 adrenocortical carcinomas). We used highly sensitive and specific quantitative RT-PCR techniques for each of the newly characterized human vasopressin receptors: V1, V2, and V3. The V1 messenger ribonucleic acid (mRNA) was detected in normal adrenal cortex and in all tumors. Its level varied widely between 2.0 × 102...