ANAEROBIC THRESHOLD CAN PROVOKE MICROALBUMINURIA IN NON-INSULIN-DEPENDENT DIABETICS

We examined two groups of non-insulin-dependent diabetic men (group A, 13 patients without microalbuminuria; group B, 9 patients with interm ittent microalbuminuria) to ascertain whether the anaerobic threshold (AT) can provoke microalbuminuria, comparing them with 12 healthy subj ects matched for age and sex (group C). All subjects exercised on a bi cycle ergometer until the AT was reached. In intermittent microalbumin uria, the albumin:creatinine ratio (ACR) was over 0.25 mg/mmol Cr 1-3- fold in 5 measurements. The ACR after exercise was increased to over 0 .25 mg/mmol.Cr in 4/9 cases in group B (P < 0.05), in 2/13 cases in gr oup A, but not at all in group C. We also studied the mechanism of exe rcise-induced microalbuminuria. In group B, ACR before exercise correl ated positively with the baseline plasma glucose. Furthermore, positiv e correlation was found between ACR after exercise and HbA(lc) in grou p B. The AT did not affect the urinary beta(2)-microglobulin in any gr oups. The plasma atrial natriuretic factor (ANF) after exercise was el evated most prominently in group B (P < 0.05). Positive correlation wa s found between increments of ACR and increments of plasma ANF after e xercise in group B. We conclude that the AT can provoke microalbuminur ia in some non-insulin-dependent diabetics. The plasma ANF and metabol ic control may play an important role in the pathophysiology of exerci se-induced microalbuminuria.