is this explained by an overexpression of vasopressin receptors?
OBJECTIVE: Abnormal responsiveness to arginine vasopressin (AVP) was previously observed in cortisol-producing adrenocortical tumours but the mechanism remains unclear. The aim of this study was to characterize the effect of AVP on cortisol secretion from adrenocortical tumours compared to normal human adrenal gland. DESIGN: A multicentre study based on pharmacological, molecular and immunohistochemical experiments performed in adenomatous and normal adrenal tissues. PATIENTS: Twenty patients with adrenocortical adenomas and subclinical Cushing’s syndrome (SCCS) or Cushing’s syndrome (CS) were compared to six control normal subjects. MEASUREMENTS: In vivo and in vitro cortisol response to vasopressin, vasopressin receptor subtype mRNA measurement by real-time polymerase chain reaction (RT-PCR), immunohistochemical localization of AVP and its V1a receptor in tumour and normal adrenal tissues. RESULTS: Terlipressin in vivo enhanced cortisol plasma levels in 17/20 SCCS and 3/6 CS but in n
