Novel regulator of vasopressin secretion: phoenixin

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2018-04, Vol.314 (4), p.R623-R628
• Main Authors: Gasparini, Silvia, Stein, Lauren M, Loewen, Spencer P, Haddock, Christopher J, Soo, Jasmine, Ferguson, Alastair V, Kolar, Grant R, Yosten, Gina L C, Samson, Willis K
• Format: Article
• Language: English
• Subjects: Animals; Arginine Vasopressin - blood; Arginine Vasopressin - metabolism; Brain slice preparation; Depolarization; Explants; Female; Gene expression; Gene Expression Regulation; Genes, fos; Homeostasis; Hypothalamic Hormones - administration & dosage; Hypothalamic Hormones - pharmacology; Hypothalamic Hormones - physiology; Hypothalamo-Hypophyseal System - drug effects; Hypothalamo-Hypophyseal System - metabolism; Hypothalamus; In Vitro Techniques; Injections, Intraventricular; Intracerebroventricular administration; Male; Membrane Potentials; Nuclei; Oxytocin; Oxytocin - metabolism; Paraventricular Hypothalamic Nucleus - drug effects; Paraventricular Hypothalamic Nucleus - metabolism; Peptide Hormones - physiology; Peptides; Pituitary; Pituitary (anterior); Pituitary (posterior); Rapid Report; Rats; Rats, Sprague-Dawley; Rodents; Secretion; Secretory Pathway - drug effects; Supraoptic Nucleus - drug effects; Supraoptic Nucleus - metabolism; Vasopressin
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00426.2017

The newly described hypothalamic peptide, phoenixin, is produced in the hypothalamus and adenohypophysis, where it acts to control reproductive hormone secretion. Both phoenixin and its receptor GPR173 are expressed in the hypothalamic supraoptic (SON) and paraventricular (PVN) nuclei, suggesting additional, nonreproductive effects of the peptide to control vasopressin (AVP) or oxytocin (OT) secretion. Hypothalamo-neurohypophysial explants released AVP but not OT in response to phoenixin. Intracerebroventricular administration of phoenixin into conscious, unrestrained male and female rats significantly increased circulating AVP, but not OT, levels in plasma, and it increased immediate early gene expression in the supraoptic nuclei of male rats. Bath application of phoenixin in hypothalamic slice preparations resulted in depolarization of PVN neurons, indicating a direct, neural action of phoenixin in the hypothalamus. Our results suggest that the newly described, hypothalamic peptide phoenixin, in addition to its effects on hypothalamic and pituitary mechanisms controlling reproduction, may contribute to the physiological mechanisms regulating fluid and electrolyte homeostasis.