Campbell S E, Febbraio M A
Department of Physiology, The University of Melbourne, Parkville, Victoria 3010, Australia.
Am J Physiol Endocrinol Metab. 2002 May;282(5):E1139-46. doi: 10.1152/ajpendo.00184.2001.
This study examined the roles of the female sex steroids, 17beta-estradiol (E(2)) and progesterone (Prog), on glucose uptake and GLUT4 protein expression. Female Sprague-Dawley rats were either sham operated (C) or ovariectomized and treated with placebo (O), E(2) (E), Prog (P), or both hormones at physiological doses (P + E) or the same dose of Prog with a high dose of E(2) (P + HiE) via timed-release pellets inserted at the time of surgery, 15 days before metabolic testing. On the morning of day 15, animals received a 300-microCi injection (ip) of 2-deoxy-[(14)C]glucose and then either exercised on a motorized treadmill for 30 min at 0.35 m/s or remained sedentary in their cages for the same period. Basal glucose uptake was not different between the treatment groups in either the red or white quadriceps. However, glucose uptake was decreased (P < 0.05) in O, P, and P + E rats during exercise in the red quadriceps compared with C rats, whereas E and P + HiE treatment restored glucose uptake. Glycogen content in skeletal muscle followed similar trends, with no differences seen in resting animals. Postexercise red quadriceps glycogen levels were higher (P < 0.05) in the E and P + HiE rats compared with O and P. Treatment of ovariectomized rats with progesterone (P rats) decreased (P < 0.05) GLUT4 content in the red quadriceps by 21% compared with C rats. These data demonstrate that estrogen-deficient animals have a decreased ability for contraction-stimulated glucose uptake and increased glycogen use during aerobic exercise. However, changes in contraction-stimulated glucose uptake could not be explained by altered transporter protein content, since the absence of E(2) had no effect on GLUT4 protein.
本研究考察了雌性甾体激素17β-雌二醇（E₂）和孕酮（Prog）在葡萄糖摄取及葡萄糖转运蛋白4（GLUT4）蛋白表达方面的作用。将雌性斯普拉格-道利大鼠分为假手术组（C）或卵巢切除并用安慰剂处理组（O）、E₂处理组（E）、Prog处理组（P）、生理剂量的两种激素联合处理组（P + E）或相同剂量的Prog与高剂量E₂联合处理组（P + HiE），于手术时（代谢测试前15天）通过植入缓释微丸给药。在第15天上午，动物腹腔注射300微居里的2-脱氧-[(¹⁴)C]葡萄糖，然后一部分在电动跑步机上以0.35米/秒的速度运动30分钟，另一部分在笼中静卧相同时间。在红色或白色股四头肌中，各处理组之间的基础葡萄糖摄取无差异。然而，与C组大鼠相比，O组、P组和P + E组大鼠在红色股四头肌运动期间的葡萄糖摄取降低（P < 0.05），而E组和P + HiE组处理可恢复葡萄糖摄取。骨骼肌中的糖原含量遵循相似趋势，静息动物未见差异。与O组和P组相比，运动后E组和P + HiE组大鼠红色股四头肌中的糖原水平更高（P < 0.05）。与C组大鼠相比，用孕酮处理卵巢切除大鼠（P组大鼠）使红色股四头肌中的GLUT4含量降低了21%（P < 0.05）。这些数据表明，雌激素缺乏的动物在有氧运动期间收缩刺激的葡萄糖摄取能力降低且糖原利用增加。然而，收缩刺激的葡萄糖摄取变化无法通过转运蛋白含量改变来解释，因为E₂缺乏对GLUT4蛋白无影响。
