A Cellular and Molecular Basis for the Selective Desmopressin-Induced ACTH Release in Cushing Disease Patients: Key Role of AVPR1b Receptor and Potential Therapeutic Implications

• Published in: The journal of clinical endocrinology and metabolism 2013-10, Vol.98 (10), p.4160-4169
• Main Authors: Luque, R. M, Ibáñez-Costa, A, López-Sánchez, L. M, Jiménez-Reina, L, Venegas-Moreno, E, Gálvez, M. A, Villa-Osaba, A, Madrazo-Atutxa, A. M, Japón, M. A, de la Riva, A, Cano, D. A, Benito-López, P, Soto-Moreno, A, Gahete, M. D, Leal-Cerro, A, Castaño, J. P
• Format: Article
• Language: English
• Subjects: Adenoma - blood; Adenoma - diagnosis; Adenoma - surgery; Adrenals. Adrenal axis. Renin-angiotensin system (diseases); Adrenocorticotropic Hormone - blood; Aged; Biological and medical sciences; Deamino Arginine Vasopressin; Endocrinopathies; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Humans; Male; Medical sciences; Middle Aged; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Pituitary ACTH Hypersecretion - diagnosis; Pituitary ACTH Hypersecretion - metabolism; Pituitary ACTH Hypersecretion - surgery; Pituitary Function Tests; Pituitary Gland - drug effects; Pituitary Gland - metabolism; Pituitary Neoplasms - blood; Pituitary Neoplasms - diagnosis; Pituitary Neoplasms - surgery; Prognosis; Receptors, Vasopressin - metabolism; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: endocrinology
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2013-1992

Context: Desmopressin is a synthetic agonist of vasopressin receptors (AVPRs). The desmopressin stimulation test is used in the diagnosis and postsurgery prognosis of Cushing disease (CD). However, the cellular and molecular mechanisms underlying the desmopressin-induced ACTH increase in patients with CD are poorly understood. Objective: The objectives of this study were to determine, for the first time, whether desmopressin acts directly and exclusively on pituitary corticotropinoma cells to stimulate ACTH expression/release and to elucidate the cellular and molecular mechanisms involved in desmopressin-induced ACTH increase in CD. Design: A total of 8 normal pituitaries (NPs), 23 corticotropinomas, 14 nonfunctioning pituitary adenomas, 17 somatotropinomas, and 3 prolactinomas were analyzed for AVPR expression by quantitative real-time RT-PCR. Primary cultures derived from corticotropinomas, nonfunctioning pituitary adenomas, somatotropinomas, prolactinomas, and NPs were treated with desmopressin, and ACTH secretion/expression, [Ca2+]i kinetics, and AVPR expression and/or proliferative response were evaluated. The relationship between AVPR expression and plasma adrenocorticotropin/cortisol levels obtained from desmopressin tests was assessed. Results: Desmopressin affects all functional parameters evaluated in corticotropinoma cells but not in NPs or other pituitary adenomas cells. These effects might be due to the dramatic elevation of AVPR1b expression levels found in corticotropinomas. In line with this notion, the use of an AVPR1b antagonist completely blocked desmopressin stimulatory effects. Remarkably, only AVPR1b expression was positively correlated with elevated plasma adrenocorticotropin levels in corticotropinomas. Conclusions: The present results provide a cellular and molecular basis to support the desmopressin stimulation test as a reliable, specific test for the diagnosis and postsurgery prognosis of CD. Furthermore, our data indicate that AVPR1b is responsible for the direct/exclusive desmopressin stimulatory pituitary effects observed in CD, thus opening the possibility of exploring AVPR1b antagonists as potential therapeutic tools for CD treatment.