Altered skeletal muscle glucose transport and blood lipid levels in habitual cigarette smokers

We determined whether habitual cigarette smoking alters insulin-stimulated glucose transport and GLUT4 protein expression in skeletal muscle. Vastus l ateralis muscle was obtained from 10 habitual cigarette smokers and 10 cont rol subjects using an open muscle biopsy procedure. Basal 3-O-methylglucose transport was twofold higher (P>0.01) in muscle from habitual smokers (0.0 5 +/- 0.08 vs. 1.04 +/- 0.19 mu mol ml(-1) h(-1); controls vs, smokers resp ectively). Insulin (600 pmol l(-1)) increased glucose transport 2.6-fold (P > 0.05) in muscle from control subjects, whereas no significant increase w as noted in habitual smokers. Skeletal muscle GLUT4 protein expression was similar between the groups. FFA levels were elevated in the smokers (264 +/ - 49 vs. 748 +/- 138 mu mol l(-1) for control subjects vs. smokers; P < 0.0 5), and serum triglyceride levels were increased in the smokers (0.9 +/- 0. 2 vs. 2.3 +/- 0.6 mmol l(-1) for control subjects vs. smokers; P < 0.05). S keletal muscle carnitine palmitil (acyl) transferase activity was similar b etween the groups, indicating that FFA transport into the mitochondria was unaltered by cigarette smoking. In conclusion, cigarette smoking appears to have a profound effect On glucose transport in skeletal muscle. Basal gluc ose transport is markedly elevated, whereas insulin-stimulated glucose tran sport is impaired. These changes cannot be explained by altered protein exp ression of GLUT4, but may be related to increased serum FFA and triglycerid e levels. These findings highlight the importance of identifying habitual c igarette smokers in studies aimed at assessing factors that lead to alterat ions in lipid and glucose homeostasis in people with non-insulin-dependent diabetes mellitus (NIDDM).