The activity of the renin-angiotensin-aldosterone system before and during submaximal bicycle exercise in relation to circulatory catecholamines in patients with type 1 (insulin-dependent) diabetes mellitus.

To evaluate the renin-angiotensin-aldosterone system in relation to circulatory catecholamines, we determined renin activity, angiotensin II, aldosterone, adrenaline, and noradrenaline in plasma before and during a submaximal bicycle exercise test in 23 Type 1 (insulin-dependent) diabetic patients (aged 19-57 years, mean 37; duration of diabetes 2-32 years, mean 16), 17 with signs of cardiac autonomic neuropathy, and in 18 healthy non-diabetic subjects (aged 24-41 years, mean 29). At rest, Type 1 diabetic patients showed significantly lower aldosterone values than control subjects (0.14 +/- 0.02 nmol/l and 0.22 +/- 0.02 nmol/l; p less than 0.01) while renin activity (1.0 +/- 0.1 nmol.l-1.h-1 and 0.9 +/- 0.1 nmol.l-1.h-1) and angiotensin II (14 +/- 1 nmol/l and 18 +/- 2 nmol/l) did not differ significantly between patients and control subjects. During exercise, increments (increase from the resting value to the value at 80% of maximal working capacity) in renin (1.5 +/- 0.4 nmol.l-1.h-1 and 3.7 +/- 0.5 nmol.l-1.h-1; p less than 0.001), angiotensin II (28 +/- 8 nmol/l and 60 +/- 8 nmol/l; p less than 0.001), aldosterone (0.16 +/- 0.04 nmol/l and 0.25 +/- 0.05 nmol/l; p less than 0.05), adrenaline (1.96 +/- 0.49 nmol/l and 2.92 +/- 0.51 nmol/l; p less than 0.05), and noradrenaline (12.01 +/- 1.25 nmol/l and 18.74 +/- 1.45 nmol/l; p less than 0.01) were significantly lower in the patients than in control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)