Division of Endocrinology and Metabolism, Mayo College of Medicine, Rochester, MN, USA.
Diabetes. 2012 Nov;61(11):2691-700. doi: 10.2337/db11-1478. Epub 2012 Jun 29.
Evaluation of the existence of a diurnal pattern of glucose tolerance after mixed meals is important to inform a closed-loop system of treatment for insulin requiring diabetes. We studied 20 healthy volunteers with normal fasting glucose (4.8 ± 0.1 mmol/L) and HbA(1c) (5.2 ± 0.0%) to determine such a pattern in nondiabetic individuals. Identical mixed meals were ingested during breakfast, lunch, or dinner at 0700, 1300, and 1900 h in randomized Latin square order on 3 consecutive days. Physical activity was the same on all days. Postprandial glucose turnover was measured using the triple tracer technique. Postprandial glucose excursion was significantly lower (P < 0.01) at breakfast than lunch and dinner. β-Cell responsivity to glucose and disposition index was higher (P < 0.01) at breakfast than lunch and dinner. Hepatic insulin extraction was lower (P < 0.01) at breakfast than dinner. Although meal glucose appearance did not differ between meals, suppression of endogenous glucose production tended to be lower (P < 0.01) and insulin sensitivity tended to be higher (P < 0.01) at breakfast than at lunch or dinner. Our results suggest a diurnal pattern to glucose tolerance in healthy humans, and if present in type 1 diabetes, it will need to be incorporated into artificial pancreas systems.
评估混合餐后葡萄糖耐量是否存在昼夜节律对于告知胰岛素需求型糖尿病的闭环治疗系统非常重要。我们研究了 20 名空腹血糖正常（4.8 ± 0.1mmol/L）和 HbA1c（5.2 ± 0.0%）的健康志愿者，以确定非糖尿病个体中是否存在这种模式。在连续 3 天内，以随机拉丁方顺序在 0700、1300 和 1900 小时期间早餐、午餐和晚餐时摄入相同的混合餐。所有天的体力活动相同。使用三示踪剂技术测量餐后葡萄糖周转。与午餐和晚餐相比，早餐后的餐后葡萄糖波动明显较低（P < 0.01）。β细胞对葡萄糖的反应性和处置指数在早餐时高于午餐和晚餐（P < 0.01）。早餐时肝胰岛素提取低于晚餐（P < 0.01）。尽管每餐的葡萄糖出现没有差异，但内源性葡萄糖生成的抑制作用在早餐时趋于较低（P < 0.01），而胰岛素敏感性在早餐时趋于较高（P < 0.01）。我们的结果表明健康人中存在葡萄糖耐量的昼夜节律，如果在 1 型糖尿病中存在，它将需要纳入人工胰腺系统。
