Platelet sodium and potassium ATPase [corrected] activity and noradrenaline efflux rate in relation to autonomic and peripheral nerve function in insulin-dependent diabetic patients.

Low sodium and potassium adenosine triphosphatase (ATPase) activity has been proposed as a mechanism behind diabetic neuropathy. In this study the platelet ATPase activity and platelet noradrenaline efflux rate were determined in 47 insulin-dependent diabetes mellitus (IDDM) patients and 20 controls. Ulnar motor conduction velocities, tested in a subgroup, were lower in patients than in controls (52.7 +/- 1.3 m s-1 vs. 61.3 +/- 1.4 m s-1; P less than 0.001). Platelet ATPase activity tended to be increased in the patients compared with the controls (29.9 +/- 1.0 x 10(-3) min-1 vs. 26.9 +/- 1.1 x 10(-3) min-1; NS). In ulnar nerve function tested subjects, ATPase activity was higher in patients than in controls (31.2 +/- 1.7 x 10(-3) min-3 vs. 25.9 +/- 1.3 x 10(-3) min-1; P less than 0.01). The platelet noradrenaline efflux rate tended to be higher in patients with lower brake indices, a sign of autonomic neuropathy, than in controls (29.0 +/- 3.0 x 10(-3) min-1 vs. 21.2 +/- 0.9 x 10(-3) min-1; P less than 0.05). The platelet ATPase activity was not decreased in IDDM patients, however, a connection between diabetic autonomic neuropathy and platelet transmittor leakage was indicated.