RELATIONSHIPS AMONG PLASMA-ALDOSTERONE, HIGH-DENSITY-LIPOPROTEIN CHOLESTEROL, AND INSULIN IN HUMANS

To investigate the pathogenesis of hypertension in patients with obesi ty and insulin resistance and to explore the role of plasma lipids, we studied 30 subjects at the end of 7 days of low (20 mEq/d) then high (200 mEq/d) sodium diets. Glucose and insulin tolerance tests were per formed at the end of each week and blood and urine collected for measu rements of plasma aldosterone, renin activity, electrolytes, insulin, and lipoproteins. There was a strong negative correlation between plas ma aldosterone and high-density lipoprotein cholesterol during both di ets. There were weaker positive correlations between plasma aldosteron e and insulin or triglycerides. When the aldosterone-renin ratio was t he dependent variable and the correlation controlled for serum potassi um, the inverse relationship with high-density lipoprotein cholesterol and the positive correlation with insulin remained, but only during t he high salt diet. Subjects were divided into three groups based on hi gh-density lipoprotein cholesterol. Subjects with the lowest high-dens ity lipoprotein cholesterol levels showed the highest aldosterone, pla sma triglycerides, body mass index, and waist-to-hip ratio. Those subj ects also demonstrated the greatest resistance to insulin action on gl ucose and plasma unesterified fatty acids. There was a weak direct cor relation between plasma aldosterone and systolic blood pressure during the high salt diet. These data suggest that high aldosterone levels m ay be a link between dyslipidemia, insulin resistance, and hypertensio n, a relationship made more evident by high salt intake.