PLASMA-CATECHOLAMINES AND RENIN IN DIABETES-MELLITUS - RELATIONSHIPS WITH POSTURE, AGE, SODIUM, AND BLOOD-PRESSURE

Plasma and urinary norepinephrine (PNE, UNE) and epinephrine, plasma renin activity (PRA) and their interrelations with posture, age, the body sodium-volume state and blood pressure were analyzed in 90 normal and 100 non-azotemic diabetic subjects. Ages ranged from 18 to 76 yrs, urinary sodium from 51 to 249 mEq/24h. Fortysix patients had a normal supine blood pressure, 54 had hypertension. Diabetics had an increased (p<0.01) mean exchangeable sodium, while blood volume was normal. Upright posture caused a comparable increase in PNE in normal and diabetic subjects; but the response of PRA was blunted (p<0.001) in diabetics, with subnormal responsiveness in 32% of cases. Epinephrine levels in diabetics were normal and unchanged with posture or age. In both groups supine and upright PNE and PRA correlated (p<0.05) positively with age, but not with urinary sodium. Comparison with dynamic normal ranges relative to age revealed low upright PNE in 14% and low or high PRA in 12 and 6% of diabetics, respectively. The low-norepinephrine subgroup had a higher exchangeable sodium and lower PRA than the normal-norepinephrine patients (p<0.025). Low-renin patients had a higher exchangeable sodium and lower UNE than normal or high-renin patients. Orthostatic decrease in blood pressure was noted in low or normal-renin, but not in high-renin patients. These findings suggest that patients with non-azotemic diabetes mellitus have usually a normal adrenergic response to postural changes; and physiological variations of PNE and PRA with age are largely maintained. However, diminished renin-responsiveness is common. Distinct sodium retention could contribute to norepinephrine or renin suppression in some patients and possibly also to the frequent development of hypertension in diabetes mellitus. © 1979 Springer-Verlag.