INS and type 2 diabetes mellitus: p38 MAPK is activated in muscle of humans with type 2 diabetes,10, 11 and of mice following lipid infusion;12 however, p38 MAPK inhibition did not improve insulin-stimulated muscle glucose uptake.11 There are reports that SB239063 inhibits glucose uptake in muscle cell lines13 perhaps independent of p38 MAPK,14 and our results suggest that SB239063 alone decreased glucose utilization in vivo.