Metabolic Markers of Hyperinsulinaemia in Normotensive Maori and Caucasian New Zealanders

New Zealand Maori are hyperinsulinaemic and insulin resistant, compared with age- and blood pressure-matched Caucasians and are therefore an important group in which to study previously described metabolic correlates of insulin resistance, including plasma urate, triglycerides and erythrocytic sodium. Only fasting triglycerides were associated with hyperinsulinaemia. Erythrocyte sodium and plasma urate were not correlated with fasting or stimulated insulin in either race. The reduced fractional urate clearance in Maori, compared with Caucasians, was positively correlated with fractional lithium clearance (proximal tubular sodium reabsorption), suggesting an ethnically expressed dependence of urate clearance on proximal tubular sodium reabsorption. Our findings indicate the need for caution in the generalisability of the variously described "markers" of hyperinsulinaemia.