Sano H, Matsunobu S, Abe T, Terashima Y
Faculty of Animal Science, Kitasato University, Aomori, Japan.
J Anim Sci. 1992 Nov;70(11):3514-20. doi: 10.2527/1992.70113514x.
Hyperglycemic clamp and hyperinsulinemic euglycemic clamp techniques were used to investigate effects of diet and cold exposure on insulin responsiveness to glucose and tissue responsiveness and sensitivity to insulin in adult rams. The sheep were fed a high-concentrate diet (80% concentrate and 20% roughage) and a high-roughage diet (20% concentrate and 80% roughage), both 70% above the ME requirement for maintenance, and were exposed to a thermoneutral environment (20 degrees C) and a cold environment (0 degrees C) for 2 wk. The estimated ME intake was greater (P < .01) for the high-concentrate diet than for the high-roughage diet. In the hyperglycemic clamp experiment, the ratio of the plasma insulin increment to the glucose infusion rate (insulin responsiveness to glucose) was lower during cold exposure than in the thermoneutral environment in sheep fed the high-concentrate diet but was unchanged in sheep fed the high-roughage diet. In the hyperinsulinemic euglycemic clamp experiment, the glucose infusion rate (tissue responsiveness to insulin) was higher (P < .01) for the high-concentrate diet than for the high-roughage diet, and it was also higher (P < .01) during cold exposure than in the thermoneutral environment, indicating that tissue responsiveness to insulin was intensified in sheep fed the high-concentrate diet during cold exposure associated with the higher energy intake. These results suggest that both reduced insulin responsiveness and enhanced tissue responsiveness to insulin in sheep exposed to cold were dependent on the type of diet.
采用高血糖钳夹和高胰岛素正常血糖钳夹技术，研究日粮和冷暴露对成年公羊胰岛素对葡萄糖的反应性以及组织对胰岛素的反应性和敏感性的影响。给绵羊分别饲喂高浓缩日粮（80%浓缩料和20%粗饲料）和高粗饲料日粮（20%浓缩料和80%粗饲料），两种日粮均比维持所需代谢能高70%，并将其置于热中性环境（20℃）和冷环境（0℃）中2周。高浓缩日粮的估计代谢能摄入量高于高粗饲料日粮（P <.01）。在高血糖钳夹实验中，在冷暴露期间，采食高浓缩日粮的绵羊血浆胰岛素增量与葡萄糖输注速率之比（胰岛素对葡萄糖的反应性）低于热中性环境中的绵羊，但采食高粗饲料日粮的绵羊该比值无变化。在高胰岛素正常血糖钳夹实验中，高浓缩日粮的葡萄糖输注速率（组织对胰岛素的反应性）高于高粗饲料日粮（P <.01），并且在冷暴露期间也高于热中性环境（P <.01），这表明采食高浓缩日粮的绵羊在冷暴露期间与较高能量摄入相关的组织对胰岛素的反应性增强。这些结果表明，冷暴露绵羊胰岛素反应性降低和组织对胰岛素反应性增强均取决于日粮类型。
