Composition of sweat of the horse during prolonged epinephrine (adrenaline) infusion, heat exposure, and exercise.
Temporal changes in sweat composition were studied in 4 horses during epinephrine (adrenaline) infusion (0.13 to 0.31 micrograms/kg/min for 3 hours), heat exposure (41 C, [33 C wet bulb] for 5 to 6 hours), and exercise (16 to 18 km/hr for 58 to 80 km). Four ponies also were studied during heat exposure. Sweat produced by each of the stimuli was hypertonic for Na+, K+, and Cl-. These electrolyte concentrations remained constant during the central period of the experiments, with changes occurring near the beginning and toward the end. The Na+ was significantly higher and K+ significantly lower in epinephrine-induced sweat than in heat-induced sweat, and the pattern of change in sweat Na/K ratio varied among the 3 stimuli. The Ca2+ concentration decreased with time and was hypotonic after 15 minutes of epinephrine-induced sweating. Concentrations of Mg2+ and protein decreased exponentially with time. There was a high correlation between them, although the Mg2+ was not protein-bound. Sweat urea concentration was directly related to plasma urea concentration. When plasma glucose concentration became greater than 10 to 12 mmole/L during epinephrine infusion, glucose appeared in the sweat and its concentration rose to 8 to 12 mmole/L of sweat when plasma glucose was more than 20 mmole/L.
D000818:Animals; D002118:Calcium / Q000032:analysis; D002712:Chlorides / Q000032:analysis; D004837:Epinephrine / Q000494:pharmacology*; D005947:Glucose / Q000032:analysis; D006736:Horses / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000032:analysis; D005082:Physical Exertion; D011188:Potassium / Q000032:analysis; D011506:Proteins / Q000032:analysis; D012964:Sodium / Q000032:analysis; D013542:Sweat / Q000032:analysis* / Q000187:drug effects; D013546:Sweating / Q000187:drug effects; D014508:Urea / Q000032:analysis
D002712:Chlorides; D011506:Proteins; D014508:Urea; D012964:Sodium; D008274:Magnesium; D005947:Glucose; D011188:Potassium; D002118:Calcium; D004837:Epinephrine