Urinary Dopamine, Noradrenaline and Adrenaline in Type 2 Diabetic Patients With and Without Nephropathy

Summary

We measured the urinary excretions of dopamine, noradrenaline and adrenaline, their conjugated metabolites, urinary excretion of sodium and creatinine clearance simultaneously in 21 patients with Type 2 (non-insulin-dependent) diabetes and 6 normal subjects. The mean (± SEM) value for urinary excretion of dopamine (52.4 ± 8.8 μg/day) in diabetic patients with nephropathy (Group C, n = 12) was significantly lower (P < 0.01) than in the normal subjects (Group A, 179.7 ± 15.5 μg/day) and in diabetic patients without nephropathy (Group B, n = 9, 131.5 ± 16.5 μg/day). The mean values for the urinary excretions of noradrenaline and adrenaline were also significantly lower (P < 0.01) in Group C than in Groups A and B. In addition, the mean urinary excretion of conjugated metabolite of dopamine in Group C was significantly lower (P < 0.05) than in Group A. There was a trend toward the observation that the mean 24-h urinary excretion of sodium in Group C (121.6 < 12.9 mEq) was lower as compared with that in Group A (140.8 ± 8.9 mEq) or B(150.7 ± 17.9 mEq). A multiple regression analysis revealed that the 24-h u rinary excretion of dopamine correlated significantly with creatinine clearance, systolic (P < 0.01) and diastolic (P < 0.05) blood pressures. The results indicate that synthesis or secretion of renal dopamine might decrease with a progression of diabetic nephropathy. However, a hypothetical consideration that a decrease in urinary dopamine output or renal dopamine might be related to a decrease in the urinary sodium excretion in Type 2 diabetic patients with and without nephropathy was not confirmed in the present study.

Key-Words

Urinary Dopamine Output - Diabetic Nephropathy - Urinary Sodium Excretion - Renal Function - Blood Pressure