Aldosterone in obesity

Plasma aldosterone levels were measured in adults whose body mass index ran ged from lean to obese. Blood was drawn while subjects rested supine for 30 -90 minutes. Aldosterone was higher in obese subjects, but could not be exp lained by renin or K+. The best predictors of plasma aldosterone were abdom inal obesity measured as waist/hip ratio or by CT scan, and insulin resista nce measured by insulin or oral glucose tolerance tests, or euglycemic clam p. In one cohort, these correlations were limited to women; in the other, t hey were also found in men. In the women with a strong correlation between aldosterone and visceral fat, aldosterone also correlated with cortisol and DHEA-S. The data are consistent with an effect of visceral fat on adrenal steroidogenesis. Visceral adipocytes have a high rate of triglyceride turno ver, and their circulation drains directly to the liver. In an experiment b ased on these characteristics, rat hepatocytes responded to fatty acids by releasing an unidentified secretagogue that stimulated aldosterone producti on by rat adrenal glomerulosa cells. The clinical data suggest that aldoste rone participates in hypertension associated with the "Insulin Resistance S yndrome". The adrenal in viscerally obese subjects may be driven by a secre tagogue released from the liver by fatty acids from abdominal adipocytes.