Non-insulin-mediated glucose uptake in several insulin-resistant states in the postabsortive period

The aim of our work was to study non-insulin-mediated glucose uptake (NIMGU), in the postabsorptive state, in several pathologies characterized by peripheral insulin resistance, namely, obesity (n=10), NIDDM (n=7), acromegaly (n=7) and Cushing's disease (n=6). These groups were compared with a group of 16 healthy subjects. To estimate peripheral insulin sensitivity (S-1) and glucose effectiveness (S-G), we used the minimal model of glucose metabolism. Although all of these pathologies showed severe insulin resistance (control: 6.44+/2.63, obesity: 2.84 i 1.57, NIDDM: 1.71 i 0.77, acromegaly: 1.88+/-1.23, Cushing's disease: 1.87+/-0.66 x 10(-4) min(-1) (mu U/ml)(-1), P<0.01), fasting insulin-mediated glucose uptake (IMGU) did not differ significantly among the five groups, because reactive hyperinsulinaemia was present in all of these states. The contribution of' NIMGU to whole-body glucose uptake did not differ significantly among the five groups (control: 77+/-8%; obesity. 77+/-9%; acromegaly: 82+/-8%; Cushing's disease: 83+/-8%; NIDDM: 84+/-7%). In conclusion, our data show that, in the postabsorptive period, non-insulin mediated glucose uptake is a major determinant of glucose disposal and is similar in the different pathologies studied; on the other hand, although absolute rates of basal insulin-mediated glucose uptake are reduced in insulin-resistant states, they did not achieve statistical value compared with control subjects because of compensatory hyperinsulinaemia. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.