Endurance training increases muscle content of glucose transporter proteins (GLUT-4) but decreases glucose utilization during exercise at a given absolute submaximal intensity. We hypothesized that glucose uptake might be higher in trained vs. untrained muscle during heavy exercise in the glycogen-depleted state. Eight untrained subjects endurance trained one thigh for 3 wk using a knee-extenso...

The characteristics and modulation of glucose transport were investigated in skeletal muscles of 5-wk-old Muscovy ducklings ( Cairina moschata). Glucose uptake by sarcolemmal vesicles isolated from gastrocnemius muscle followed typical Michaelis-Menten kinetics with a K m value (17 mM) similar to that described in equivalent mammalian preparations. Western blot analysis of duckling sarcolemma u...

Exercise increases the rate of glucose uptake into the contracting skeletal muscles. This effect of exercise is similar to the action of insulin on glucose uptake, and the mechanism through which both stimuli increase skeletal muscle glucose uptake involves the translocation of GLUT-4 glucose transporters to the plasma membrane and transverse tubules. Most studies suggest that exercise and insu...

Previous studies have suggested that alteration in the expression of the insulin-regulatable glucose transporter of muscle (GLUT4 protein) may be an important determinant of insulin action. In the present studies, we have examined GLUT4 mRNA and protein concentrations in muscle after variations in the metabolic status of the intact animal (i.e., 7 d streptozotocin-induced diabetes, 7 d insulin-...

Glucose utilization during exercise of a given submaximal power output is decreased after endurance training. The aim of the present study was to elucidate the mechanisms behind this phenomenon by utilizing the sarcolemmal giant vesicle technique. Eight healthy young untrained men endurance trained one thigh for 3 wk. They then exercised both thighs simultaneously at the same work load (77% of ...

Pancreatic β-cells dysfunction and impairment of insulin action usually leads to hyperglycemia. Punica granatum L. is a well-known traditional herbal remedy in Iran due to its positive effects on ameliorating blood glucose homeostasis. In this study, we aimed to investigate and compare the pomegranate fruits aqueous extract (PE) on glucose and lipid metabolisms in normal and Alloxan-induced dia...

Insulin signaling was examined in muscle made insulin resistant by short-term (24-h) denervation. Insulin-stimulated glucose transport in vitro was reduced by 28% (P < 0.05) in denervated muscle (DEN). In control muscle (SHAM), insulin increased levels of surface-detectable GLUT-4 (i.e., translocated GLUT-4) 1.8-fold (P < 0.05), whereas DEN surface GLUT-4 was not increased by insulin (P > 0.05)...

The influence of muscle glycogen content on basal and contraction-induced glucose transport and cell surface GLUT-4 content was studied in rat skeletal muscle. Wistar rats were preconditioned by a combination of swimming exercise and diet, resulting in 40% lower (LG) or threefold higher (HG) muscle glycogen content compared with nonexercised controls (NG). At rest and during contractions, 2-deo...

Studies in rodents have established that GLUT-4 translocation is the major mechanism by which insulin and exercise increase glucose uptake in skeletal muscle. In contrast, much less is known about the translocation phenomenon in human skeletal muscle. In the current study, nine healthy volunteers were studied on two different days. On one day, biopsies of vastus lateralis muscle were taken befo...

Pancreatic β-cells dysfunction and impairment of insulin action usually leads to hyperglycemia. Punica granatum L. is a well-known traditional herbal remedy in Iran due to its positive effects on ameliorating blood glucose homeostasis. In this study, we aimed to investigate and compare the pomegranate fruits aqueous extract (PE) on glucose and lipid metabolisms in normal and Alloxan-induced dia...