The relationship of the renin-angiotensin-aldosterone system to atrial natriuretic peptide and the natriuresis of volume expansion in diabetics with and without proteinuria.

Atrial natriuretic peptide (ANP) and the renin-angiotensin-aldosterone system are important regulatory hormones in sodium homeostasis. We have measured these hormones during volume expansion produced by water immersion in diabetic subjects without and with microalbuminuria or frank proteinuria and compared the response with normal controls. Diabetic subjects excreted about half the amount of sodium that was excreted by the normal subjects (39 vs 21 mmol) over 4 h. Diabetic subjects and normal ones showed a twofold rise in ANP during immersion and a marked suppression of both plasma renin activity and aldosterone. There was no difference in the hormonal response between diabetic and normal subjects or between those diabetic subjects with and those without incipient (microalbuminurics) or established nephropathy.