Increased Plasma Atrial Natriuretic Factor and Reduced Plasma Renin in Patients with Poorly Controlled Diabetes Mellitus

To investigate atrial natriuretic factor (ANF) and its relationship to the renin system in diabetes, we measured plasma immunoreactive ANF and plasma renin activity (PRA) in 27 non-ketotic diabetic patients without evidence of cardiac or overt renal disease, and compared them with 26 age- and sex-matched normal subjects. 2. Diabetic patients were divided prospectively into poor (PGC, n = 14) or moderate (MGC, n = 13) glycaemic control depending on their concurrent plasma glycohaemoglobin (HbA1) levels ( 9% or 9%, respectively). Plasma ANF was elevated in PGC diabetic patients (15.7 ± 1.8 fmol/ml, mean ± sem) compared with MGC diabetics (9.9 ± 0.8 fmol/ml, P 0.001) and normal subjects (10.1 ± 1.3 fmol/ml, P 0.05). 3. In contrast, PRA was lower in the PGC diabetic patients (1.3 ± 0.3 pmol of angiotensin I h−1 ml−1) compared with the other groups (2.5 ± 0.5 and 2.1 ± 0.2 pmol of angiotensin I h−1 ml−1, P 0.05). Diabetic groups had proportionally more patients with high prorenin values (over 30 ng h−1 ml−1) than the normal group, but there was no difference between the diabetic groups. 4. Among the diabetic patients, ANF was directly related to HbA1 (r = 0.49, P 0.005) and urinary albumin excretion (r = 0.40, P 0.02), and was inversely related to PRA (r = −0.36, P 0.04) and plasma creatinine (r = −0.42, P 0.02). 5. Systolic blood pressure was greater in PGC diabetic patients 133 ± 5 mmHg (17.7 ± 0.7 kPa) than in MGC diabetic patients 117 ± 4 (15.6 ± 0.5 kPa), P 0.05 and normal subjects 121 ± 3 (16.1 ± 0.4 kPa), P 0.05. Diastolic pressure was not significantly different among the groups. 6. The directionally opposite changes in plasma ANF and plasma renin in PGC diabetic patients may reflect a normal response to expansion of intravascular volume. It remains to be established whether these changes are factors in the early renal dysfunction of diabetes mellitus.