Basal glucose metabolism in type 2 diabetes. A critical review

In the current review we have re-evaluated the concept of markedly elevated basal glucose production rates in patients with Type 2 diabetes. Owing to underpriming of the enlarged glucose pool in hyperglycaemic Type 2 diabetic patients most previous studies using the primed-continuous tracer infusion technique may have markedly overestimated basal glucose production rates in proportion to the level of hyperglycaemia. Also previous studies using an adequate priming ratio may have overestimated glucose production to some extent due to assumptions of steady state conditions. Using adjusted priming and non-steady state calculations we have found near normal rates of basal glucose production and glucose utilization in obese patients with Type 2 diabetes. The presence of insulin resistance in these patients was confirmed using the euglycaemic clamp technique. Thus, it is suggested that the basal state in Type 2 diabetes may be considered as a compensated condition where glucose turnover rates are maintained near normal. Hyperinsulinaemia and hyperglycaemia may serve as compensating factors, compensating for the defects in insulin action.