Strenuous exercise induces delayed-onset muscle damage including oxidative damage of cellular components. Oxidative stress to muscle cells impairs glucose uptake via disturbance of insulin signaling pathway. We investigated glucose uptake and insulin signaling in relation to oxidative protein modification in muscle after acute strenuous exercise. ICR mice were divided into sedentary and exercise groups. Mice in the exercise group performed downhill running exercise at 30 m/min for 30 min. At 24 hr after exercise, metabolic performance and insulin-signaling proteins in muscle tissues were examined. In whole body indirect calorimetry, carbohydrate utilization was decreased in the exercised mice along with reduction of the respiratory exchange ratio compared to the rested control mice. Insulin-stimulated uptake of 2-deoxy-[3 H]glucose in damaged muscle was decreased after acute exercise. Tyrosine phosphorylation of insulin receptor substrate (IRS)-1 and phosphatidyl-3-kinase/Akt signaling were impaired by exercise, leading to inhibition of the membrane translocation of glucose transporter 4. We also found that acute exercise caused 4-hydroxy-nonenal modification of IRS-1 along with elevation of oxidative stress in muscle tissue. Impairment of insulin-induced glucose uptake into damaged muscle after strenuous exercise would be related to disturbance of insulin signal transduction by oxidative modification of IRS-1., W. Aoi ... [et al.]., and Obsahuje seznam literatury
Fibroblast growth factor 21 (FGF21) is a novel metabolic regulator produced primarily by the liver that exerts potent antidiabetic and lipid-lowering effects in animal models of obesity and type 2 diabetes mellitus. This hormone contributes to body weight regulation and is strongly involved in the response to nutritional deprivation and ketogenic state in mice. The principal sites of metabolic actions of FGF21 are adipose tissue, liver and pancreas. Experimental studies have shown marked improvements in diabetes compensation and dyslipidemia after FGF21 administration in diabetic mice and primates. Positive metabolic actions of FGF21 without the presence of apparent side effects make this factor a hot candidate to treat type 2 diabetes and accompanying metabolic diseases. The aim of this review is to summarize the current knowledge about the metabolic effects of FGF21 including some preliminary data on changes of its levels in humans with a special emphasis on its therapeutic potential in type 2 diabetes mellitus., I. Dostálová, D. Haluzíková, M. Haluzík., and Obsahuje seznam literatury