Tissue responsiveness and sensitivity to insulin in sheep fed plantain and orchardgrass and exposed to cold

摘要

Abstract To assess the effect on insulin action of feeding a forage herb to sheep exposed to a cold environment, eight sheep were fed either plantain (PL), a forage herb, or orchardgrass (OR), a forage. A hyperinsulinaemic euglycaemic clamp procedure was applied to determine tissue responsiveness and sensitivity to insulin in both the thermoneutral (20°C) and cold (0–4°C) environments. For the glucose clamp procedure, insulin was infused over four sequential 2‐h periods at rates of 0.64, 1.6, 4.0, and 10 mU kg‐0.75 body weight min?1 and glucose was infused at variable rates to maintain euglycaemia. The maximal glucose infusion rate (tissue responsiveness to insulin) was greater (P = 0.04) for the PL diet than for the OR diet, and was enhanced (P = 0.001) during cold exposure. The plasma insulin concentration at half maximal glucose infusion rate (tissue sensitivity to insulin) was influenced by neither diet nor environment. No significant diet by environment interaction was observed for these variables. I...