Effect of bacteremia on skeletal muscle glucose transport in fed rats.

Basal and insulin-stimulated membrane glucose transport was studied in soleus muscles from fed rats given Escherichia coli intraperitoneally (ip, 4 X 10(10) colony forming units (CFU)/kg) or saline. Glucose transport was measured in muscles by evaluating the fractional efflux (lambda, min-1) of [14C]3-O-methylglucose (14C-3MG) after "loading" muscles with 14C-3MG. Basal glucose transport was similar in muscles from 8-hr bacteremic (B) and time-matched control (C) rats, but it was elevated significantly in muscles 12 hr after bacterial injection (B lambda = 0.0227 +/- 0.0010, n = 41, C lambda = 0.0159 +/- 0.0008, n = 42; P less than .05). The effect of insulin on transport was determined from the peak response and from the percent increase in transport for each insulin dose. At low insulin concentrations, peak glucose transport was increased in muscles from 8-hr bacteremic rats compared to controls, while the response to 10.0 mU/ml of insulin was similar in bacteremic and control rat muscles. The maximum percent increase in transport and the EC50 for insulin-mediated 3MG transport were not different in muscles from 8-hr bacteremic and time-matched control rats. Twelve hr after bacterial injection, low insulin doses stimulated sugar transport to greater peak values in bacteremic rat muscles compared to time-matched control values. However, peak 14C-3MG transport with 10.0 mU/ml of insulin was attenuated in bacteremic rat muscles compared to controls. An attenuated maximum response and slightly diminished EC50 were evident in muscles from 12-hr bacteremic rats compared to controls when the percent increase in transport at each insulin concentration was analyzed. The results of the current study were similar to results obtained in fasted rats [1] which indicates that alterations in muscle glucose transport during bacteremia are independent of dietary state.