title: Characterization of the effects of the vasopressin V2 receptor on sweating, fluid balance, and performance during exercise.
abstract: A regulatory effect of arginine vasopressin (AVP) on sweat water conservation has been hypothesized but not definitively evaluated. AVP-mediated insertion of sweat and salivary gland aquaporin-5 (AQP5) water channels through activation of the vasopressin type 2 receptor (V2R) remains an attractive, yet unexplored, mechanism that could result in a more concentrated sweat with resultant decreased water loss. Ten runners participated in a double-blind randomized control treadmill trial under three separate pharmacological conditions: a placebo, V2R agonist (0.2 mg desmopressin), or V2R antagonist (30 mg tolvaptan). After a familiarization trial, runners ran for 60 min at 60% of peak speed followed by a performance trial to volitional exhaustion. Outcome variables were collected at three exercise time points: baseline, after the steady-state run, and after the performance run. Body weight losses were <2% across all three trials. Significant pharmacological condition effects were noted for urine osmolality [F = 84.98; P < 0.0001] and urine sodium concentration ([Na(+)]) [F = 38.9; P < 0.0001], which verified both pharmacological activation and inhibition of the V2R at the kidney collecting duct. Plasma osmolality and [Na(+)] demonstrated significant exercise (F = 26.0 and F = 11.1; P < 0.0001) and condition (F = 5.1 and F = 3.8; P < 0.05) effects (osmolality and [Na(+)], respectively). No significant exercise or condition effects were noted for either sweat or salivary [Na(+)]. Significant exercise effects were noted for plasma [AVP] (F = 22.3; P < 0.0001), peak core temperature (F = 103.3; P < 0.0001), percent body weight change (F = 6.3; P = 0.02), plasma volume change (F = 21.8; P < 0.0001), and thirst rating (F = 78.2; P < 0.0001). Performance time was not altered between conditions (P = 0.80). In summary, AVP acting at V2R does not appear to regulate water losses from body fluids other than renal excretion during exercise.
authors.affiliation: Exercise Science Program, Oakland University, Rochester, Michigan; and hew@oakland.edu.
authors.forename: Tamara
authors.initials: T
authors.lastname: Hew-Butler
authors.affiliation: Exercise Science Program, Oakland University, Rochester, Michigan; and.
authors.forename: Jed
authors.initials: J
authors.lastname: Hummel
authors.affiliation: Exercise Science Program, Oakland University, Rochester, Michigan; and.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Rider
authors.affiliation: Endocrinology and Metabolism, Georgetown University Medical Center, Washington, DC.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Verbalis
mesh_terms: D000328:Adult; D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines / Q000008:administration & dosage; D015415:Biomarkers / Q000097:blood / Q000652:urine; D003894:Deamino Arginine Vasopressin / Q000008:administration & dosage; D004311:Double-Blind Method; D015444:Exercise; D005260:Female; D006727:Hormone Antagonists / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D009481:Neurophysins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009994:Osmolar Concentration; D010807:Physical Endurance / Q000187:drug effects; D010953:Plasma Volume; D011498:Protein Precursors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017483:Receptors, Vasopressin / Q000378:metabolism*; D012420:Running; D015398:Signal Transduction; D012964:Sodium / Q000097:blood / Q000652:urine; D013542:Sweat / Q000378:metabolism; D013545:Sweat Glands / Q000187:drug effects / Q000378:metabolism*; D013546:Sweating / Q000187:drug effects; D013894:Thirst; D013997:Time Factors; D000077602:Tolvaptan; D014667:Vasopressins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014882:Water-Electrolyte Balance / Q000187:drug effects; D015431:Weight Loss; D055815:Young Adult
chemical_list: C438657:AVP protein, human; C585768:AVPR2 protein, human; D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines; D015415:Biomarkers; D006727:Hormone Antagonists; D009481:Neurophysins; D011498:Protein Precursors; D017483:Receptors, Vasopressin; D014667:Vasopressins; D000077602:Tolvaptan; D012964:Sodium; D003894:Deamino Arginine Vasopressin
keywords: V2 antagonist; arginine vasopressin; running; sweat sodium