The changes in plasma renin activity (PRA) and plasma aldosterone concentration (PA) in response to postural stimuli were evaluated in 12 patients with stable diabetes mellitus and in five volunteers. Seven diabetic patients had hyperkalemia, and several had renal insufficiency and neurological complications. Five diabetics had normal serum potassium concentration, a mean creatinine clearance within the normal range, and few complications. PRA and PA were measured in these patients and in the control subjects, all of whom were receiving a diet containing 10 mEq of sodium and 50 mEq of potassium while they were in a supine position, after they were tilted to a 90° position, and after upright posture for two hours. The results indicate that impaired responsiveness of PRA and PA may occur in patients with complicated and those with uncomplicated diabetes and may be responsible in part for a relatively high prevalence of hyperkalemia especially in those diabetic patients with reduced renal function.
(Arch Intern Med 137:852-855, 1977)