ASSOCIATION OF A NOCTURNAL RISE IN PLASMA ALPHA-ATRIAL NATRIURETIC PEPTIDE AND REVERSED DIURNAL BLOOD-PRESSURE RHYTHM IN HOSPITALIZED NORMOTENSIVE SUBJECTS WITH NON-INSULIN-DEPENDENT DIABETES-MELLITUS

Diurnal changes in plasma atrial natriuretic peptide (ANP), plasma ren in activity (PRA) and plasma aldosterone as related to those in blood pressure (BP) were studied under hospital conditions in 18 diabetic su bjects without proteinuria and 8 age-matched control subjects. Of 18 d iabetic subjects, 10 had a normal diurnal BP rhythm with the peak valu e in the afternoon (group 1) and 8 had a reversed BP rhythm with the p eak value during the night (group 2). Autonomic dysfunction estimated by measuring orthostatic BP and heart-rate changes and beat-to-beat he art-rate variations was more pronounced in group 2 than in group 1. Fa sting plasma glucose and HbA(1c), were similarly high in both diabetic groups. Group 1 showed modestly elevated mean 24-h MBP and plasma ANP levels, modestly low mean 24-h PRA and plasma aldosterone levels, and a lack of diurnal ANP changes similar to that in controls. Group 2 sh owed markedly elevated mean 24-h BP and plasma ANP levels, markedly lo w mean 24-h PRA and plasma aldosterone levels, and nocturnal rises in plasma ANP and BP. PRA and plasma aldosterone exhibited circadian rhyt hms with their peak values found in the early morning in all three gro ups. The daytime/overnight excretion ratios of sodium and water were n ormal in group 1 and low in group 2. These results indicate that diurn al changes in plasma ANP, PRA and plasma aldosterone are altered in di abetic subjects with normal and reversed diurnal BP rhythms, predomina ntly in the latter.