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Identification of a Novel Regulator of Vasopressin Secretion
Author(s) -
Stein Lauren Michelle,
Soo Jasmine,
Loewen Spencer,
Hindmarch Charles,
Ferguson Alastair,
Yosten Gina,
Samson Willis
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.714.3
Subject(s) - hypothalamus , endocrinology , medicine , vasopressin , oxytocin , receptor , neuropeptide , homeostasis , secretion , biology , estrous cycle , supraoptic nucleus , hypothalamic–pituitary–gonadal axis , chemistry , hormone , luteinizing hormone
We identified a novel hypothalamic peptide, Phoenixin, and demonstrated its hypothalamic and pituitary actions to control reproductive hormone secretion (Yosten et al. J Neuroendocrinol 25:206, 2013). We now have identified the orphan G protein‐coupled receptor, GPR173, to be the cognate receptor for Phoenixin (Stein et al. Am J Physiol 311:R489,2016). Transient compromise of either GPR173 or Phoenixin production in rat hypothalamus significantly interrupted estrous cyclicity, suggesting that this ligand‐receptor pair is essential for normal reproductive function. In situ hybridization histochemistry studies revealed that Phoenixin is expressed in neurons of the paraventricular (PVN) and supraoptic (SON) nuclei, as is GPR173. We hypothesized that in addition to its action to control reproductive physiology, Phoenixin acts in PVN and SON to control vasopressin (AVP) or oxytocin (OT) secretion. Hypothalamo‐neurohypohysial (HNS) explants released AVP but not OT in response to Phoenixin. Intracerebroventricular administration of Phoenixin into conscious, unrestrained male rats significantly increased circulating AVP, but not OT, levels in plasma. Bath application of Phoenixin in hypothalamic slice preparations resulted in depolarization of PVN neurons indicating a direct, neural action of Phoenixin in hypothalamus. Our results suggest that the newly described, hypothalamic peptide Phoenixin, in addition to its effects on hypothalamic and pituitary mechanisms controlling reproduction, may play an important role in the regulation of fluid and electrolyte homeostasis. Support or Funding Information SLU President's Research Fund