Altered erythrocyte and plasma sodium and potassium in hypertension, a facet of hyperinsulinemia.

Red blood cell sodium and potassium, plasma potassium, glucose and insulin responses to oral glucose load, serum urate, and plasma triglycerides were determined in a stratified subsample (n = 89) of a representative population sample (n = 1211), comprising 30 nonobese normotensive subjects with normal glucose tolerance (reference group) and 59 subjects representing each of the seven possible combinations of abnormal glucose tolerance, obesity, and hypertension. Rate of cation imbalance (red blood cell sodium greater than or equal to 7.0 mEq/L, potassium less than 92.5 mEq/L, or plasma potassium greater than or equal to 4.5 mEq/L) was 88.1% in subjects with abnormal tolerance, obesity, or hypertension, as compared with 40.0% in the reference group (p less than 0.001). These subjects were also characterized by significantly greater rates of insulin response: 60- and 120-minute postload levels of 100 mU/L or more (88.1 vs 46.7%), plasma triglycerides of 80 mg/dl or more (89.8 vs 53.3%) and serum uric acid of 5.5 mg/dl or more (61.0 vs 26.7%; p less than 0.001 for all). The rate of cation imbalance was significantly associated with each of these three biochemical correlates: insulin response (p less than 0.01), triglycerides (p less than 0.001), and urate (p less than 0.001). In the total population sample, the rate of untreated hypertension increased from 18% to 35% to 55.3% (p less than 0.001), with an increase in the number of biochemical correlates of cation imbalance in combination with glucose intolerance and obesity.(ABSTRACT TRUNCATED AT 250 WORDS)