Chromium supplementation does not influence glucose metabolism or insulin action in response to cold exposure in mature sheep

An isotope dilution method using [U-C-13]glucose infusion and a glucose cla mp approach were applied to determine the effects of supplemental Cr and co ld exposure on blood glucose turnover rate and tissue responsiveness and se nsitivity to insulin in eight sheep. The daily profiles of blood metabolite s and hormones were also determined. The sheep consumed diets containing ei ther 0 or 1 mg of Cr/kg from a high-Cr yeast and were exposed from a thermo neutral environment (20 degreesC) to a cold environment (0 to 4 degreesC) f or 9 d. The experiment used a crossover design. Body weight was lost (P = 0 .02) during cold exposure, regardless of Cr supplementation. Blood glucose turnover rate and the maximal glucose infusion rate did not differ between diets, but both. were higher (P = 0.0004 and P = 0.0001, respectively) duri ng cold exposure than in the thermoneutral environment. The plasma insulin concentration at half-maximal glucose infusion rate changed with neither di et nor environment. Plasma concentrations of glucose and NEFA increased (P < 0.05) during cold exposure for both diets. In sheep, Cr supplementation, 1 mg/kg of diet as high-Cr yeast, has little influence on blood glucose met abolism and insulin action, whereas cold exposure enhances both without fur ther modification by Cr supplementation.