Division of Endocrinology, Department of Medicine, Université de Sherbrooke, 3001, 12th Avenue North, J1H 5N4 Sherbrooke, Quebec, Canada.
Diabetes Metab. 2012 Feb;38(1):27-33. doi: 10.1016/j.diabet.2011.06.005. Epub 2011 Aug 23.
Adequate adipose tissue blood flow (ATBF) is essential for its metabolic and endocrine functions. From a metabolic point of view, sufficient increases in ATBF after meals permits full storage of excess energy into fat, thus protecting other tissues against the toxic effects of fatty acids and glucose spillover. It was previously shown that postprandial increases in ATBF are blunted in obese and insulin-resistant subjects, and that much of the postprandial ATBF response is the result of β-adrenergic activation. Examination of previously recorded data on postprandial ATBF responses revealed an underlying heterogeneity, with postprandial ATBF being largely unresponsive to food stimuli in a substantial proportion of normal weight healthy people (low responders). Our study tests the hypothesis that this unresponsive pattern is due to resistance to β-adrenergic stimulation in adipose tissue.
Five responders and five low responders were selected from a previously studied cohort and matched for BMI (20.5±0.7 vs 22±1 kg/m(2), respectively), gender (male/female: 2/3) and age (30±3 vs 37±6 years). Subcutaneous adipose tissue microinfusions of stepwise increasing doses of isoproterenol were performed with concomitant monitoring of blood flow, using the (133)Xenon washout technique.
Although BMI was similar between responders and low responders, there were significant differences in fat mass (9.9±1.6 vs 14.4±1.6 kg; P<0.05) and four-point skinfold thickness (33±4 vs 52±16 mm; P<0.05). Lack of ATBF response to oral glucose was confirmed in the low responder group. In responders, ATBF was higher at baseline (5.4±1 vs 3.4±1 mL/min/100 g of tissue) and responded more distinctly to increasing isoproterenol doses (10(-8) M: 7.6±1.4 vs 4.9±1; 10(-6) M: 12.5±1.7 vs 7.5±1.6; and 10(-4) M: 20 ±1.7 vs 9±0.9 mL/min/100 g of tissue).
These data suggest that the lack of glucose-stimulated ATBF is associated with resistance to sympathetic activation in adipose tissue.
足够的脂肪组织血流（ATBF）对于其代谢和内分泌功能至关重要。从代谢的角度来看，餐后 ATBF 的充分增加允许将多余的能量完全储存为脂肪，从而保护其他组织免受脂肪酸和葡萄糖溢出的毒性影响。先前的研究表明，肥胖和胰岛素抵抗患者餐后 ATBF 的增加减弱，并且餐后 ATBF 的大部分反应是β-肾上腺素能激活的结果。对餐后 ATBF 反应的先前记录数据的检查显示出潜在的异质性，其中相当一部分正常体重健康人（低反应者）对食物刺激的餐后 ATBF 反应基本无反应。我们的研究检验了这样一种假设，即这种无反应模式是由于脂肪组织对β-肾上腺素能刺激的抵抗所致。
从以前研究的队列中选择了 5 名应答者和 5 名低应答者，并按 BMI（分别为 20.5±0.7 和 22±1kg/m2）、性别（男/女：2/3）和年龄（30±3 和 37±6 岁）进行匹配。使用（133）氙气洗脱技术进行逐步增加剂量异丙肾上腺素的皮下脂肪组织微输注，并同时监测血流。
尽管应答者和低应答者的 BMI 相似，但脂肪量存在显着差异（9.9±1.6 和 14.4±1.6kg；P<0.05）和四点皮褶厚度（33±4 和 52±16mm；P<0.05）。在低应答者组中证实了口服葡萄糖对 ATBF 无反应。在应答者中，ATBF 在基线时较高（5.4±1 和 3.4±1mL/min/100g 组织），并且对异丙肾上腺素剂量的增加反应更为明显（10(-8)M：7.6±1.4 和 4.9±1；10(-6)M：12.5±1.7 和 7.5±1.6；和 10(-4)M：20±1.7 和 9±0.9mL/min/100g 组织）。
这些数据表明，葡萄糖刺激的 ATBF 缺乏与脂肪组织中交感神经激活的抵抗有关。
