Galassetti P, Shiota M, Zinker B A, Wasserman D H, Cherrington A D
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615, USA.
Am J Physiol. 1998 Jul;275(1):E101-11. doi: 10.1152/ajpendo.1998.275.1.E101.
The effect of a negative arterial-portal venous (a-pv) glucose gradient on skeletal muscle and whole body nonhepatic glucose uptake was studied in 12 42-h-fasted conscious dogs. Each study consisted of a 110-min equilibration period, a 30-min baseline period, and two 120-min hyperglycemic (2-fold basal) periods (either peripheral or intraportal glucose infusion). Somatostatin was infused along with insulin (3 x basal) and glucagon (basal). Catheters were inserted 17 days before studies in the external iliac artery and hepatic, portal and common iliac veins. Blood flow was measured in liver and hindlimb using Doppler flow probes. The arterial blood glucose, arterial plasma insulin, arterial plasma glucagon, and hindlimb glucose loads were similar during peripheral and intraportal glucose infusions. The a-pv glucose gradient (in mg/dl) was 5 +/- 1 during peripheral and -18 +/- 3 during intraportal glucose infusion. The net hindlimb glucose uptakes (in mg/min) were 5.0 +/- 1.2, 20.4 +/- 4.5, and 14.8 +/- 3.2 during baseline, peripheral, and intraportal glucose infusion periods, respectively (P < 0.01, peripheral vs. intraportal); the hindlimb glucose fractional extractions (in %) were 2.8 +/- 0.4, 4.7 +/- 0.8, and 3.9 +/- 0.5 during baseline, peripheral, and intraportal glucose infusions, respectively (P < 0. 05, peripheral vs. intraportal). The net whole body nonhepatic glucose uptakes (in mg . kg-1 . min-1) were 1.6 +/- 0.1, 7.9 +/- 1.3, and 5.4 +/- 1.1 during baseline, peripheral, and intraportal glucose infusion, respectively (P < 0.05, peripheral vs. intraportal). In the liver, net glucose uptake was 70% greater during intraportal than during peripheral glucose infusion (5.8 +/- 0.7 vs. 3.4 +/- 0.4 mg . kg-1 . min-1). In conclusion, despite comparable glucose loads and insulin levels, hindlimb and whole body net nonhepatic glucose uptake decreased significantly during portal venous glucose infusion, suggesting that a negative a-pv glucose gradient leads to an inhibitory signal in nonhepatic tissues, among which skeletal muscle appears to be the most important.
在12只禁食42小时的清醒犬中，研究了动脉-门静脉（a-pv）葡萄糖梯度为负时对骨骼肌和全身非肝脏葡萄糖摄取的影响。每项研究包括110分钟的平衡期、30分钟的基线期以及两个120分钟的高血糖期（血糖为基础值的2倍，通过外周或门静脉内输注葡萄糖）。生长抑素与胰岛素（基础值的3倍）和胰高血糖素（基础值）一起输注。在研究前17天，将导管插入髂外动脉、肝静脉、门静脉和髂总静脉。使用多普勒血流探头测量肝脏和后肢的血流量。在外周和门静脉内输注葡萄糖期间，动脉血糖、动脉血浆胰岛素、动脉血浆胰高血糖素和后肢葡萄糖负荷相似。外周葡萄糖输注期间a-pv葡萄糖梯度（mg/dl）为5±1，门静脉内葡萄糖输注期间为-18±3。基线期、外周葡萄糖输注期和门静脉内葡萄糖输注期后肢葡萄糖净摄取量（mg/min）分别为5.0±1.2、20.4±4.5和14.8±3.2（外周与门静脉内相比，P<0.01）；基线期、外周葡萄糖输注期和门静脉内葡萄糖输注期后肢葡萄糖分数提取率（%）分别为2.8±0.4、4.7±0.8和3.9±0.5（外周与门静脉内相比，P<0.05）。基线期、外周葡萄糖输注期和门静脉内葡萄糖输注期全身非肝脏葡萄糖净摄取量（mg·kg-1·min-1）分别为1.6±0.1、7.9±1.3和5.4±1.1（外周与门静脉内相比，P<0.05）。在肝脏中，门静脉内葡萄糖输注期间的葡萄糖净摄取量比外周葡萄糖输注期间高70%（5.8±0.7 vs. 3.4±0.4 mg·kg-1·min-1）。总之，尽管葡萄糖负荷和胰岛素水平相当，但门静脉内输注葡萄糖期间后肢和全身非肝脏葡萄糖净摄取量显著降低，这表明负的a-pv葡萄糖梯度会在非肝脏组织中产生抑制信号，其中骨骼肌似乎是最重要的。
