[Effect of water immersion on plasma renin activity, vasopressin and aldosterone level in diabetics]

In 83 diabetic patients (23 of them were insulin-dependent) and 34 healthy subjects the influence of water immersion (WI) for 2 hrs on plasma renin activity (PRA), plasma aldosterone and vasopressin (AVP) level was examined. In both examined groups WI exerted a suppressive effect on PRA, plasma aldosterone and AVP level. In this respect only quantitative but not qualitative differences between diabetics and normals were observed. Presence of moderately advanced diabetic nephropathy and autonomic neuropathy influenced only slightly WI induced alterations of the renin-aldosterone system and AVP secretion. In all diabetic patients a defective volumetric mechanism of both the renin-aldosterone system and AVP secretion was stated. In addition in diabetic patients with late diabetic complications a defective osmotic mechanism of AVP secretion was observed. These findings suggest participation also of factors other than hypervolemia and decrease of the plasma osmolality in the mechanism of the observed WI induced suppression of the renin-angiotensin system and AVP secretion in diabetic patients.