Tamara Hew-Bulter publishes in the American Journal of Physiology

CBR member Tamara Hew-Butler, of the Exercise Science Program in the School of Health Sciences, published a paper in the August 15 issue of the American Journal of Physiology - Regulatory, Integrative and Comparative Physiology. The paper, titled “Characterization of the effects of the vasopressin V2 receptor on sweating, fluid balance, and performance during exercise” (Volume 307, Pages R366-R375), was coauthored by two graduates of the MS program in Exercise Science, Jed Hummel and Brian Rider. The study was funded in part by a University Research Committee Faculty Fellowship Award. The goals of the study are described in these excerpts from the introduction (references removed).

ARGININE VASOPRESSIN (AVP) is the primary neuroendocrine regulator of water metabolism, acting to maintain plasma osmolality within the normal physiological range of 275–295 mosmol/kg H2O. Osmotic regulation of plasma tonicity generally occurs through activation of the vasopressin type 2 receptor (V2R) in the kidney. Activation of V2R initiates the translocation and subsequent insertion of aquaporin-2 (AQP2) water channels into the apical membrane of the collecting duct principal cells. This allows for water reabsorption along osmotic gradients and concomitant antidiuresis when plasma tonicities are high….

This primary aim of this study was to critically assess whether or not sweat water content and sodium concentration are acutely regulated by dynamic changes in AVP acting on the V2R during treadmill running. Secondary aims were to evaluate running performance and core temperature to further characterize the role of AVP in the coordinated balance of fluid and temperature homeostasis during exercise. The potential significance of positive findings could: 1) establish a plausible connection between AVP and AQP5 water channel translocation, and 2) revive scientific interest in the primitive sweat gland as an important regulator of fluid and sodium balance during endurance exercise.