The excessive release of myoglobin following extensive skeletal muscle trauma, burns, and myopathies may result in renal dysfunction. Due to its molecular size, myoglobin is filtered through the glomerulus and is in part reabsorbed by the tubular system. intraluminal deposition of myoglobin following renal hypoperfusion and the impact of endogenous mediators on cell function contribute to the pathogenesis of acute renal failure. The present study was aimed to investigate the relation between myoglobin and renal function in polytraumatized patients. Thirty-four patients with an Injury Severity Score (ISS) of 28 +/- 3.1 (SEM) and a mean age of 39.5 years (range 18-70) were studied prospectively. Myoglobin, sodium, and creatinine concentrations in plasma and urine were determined 8-hourly. Myoglobin excretion, fractional myoglobin excretion, myoglobin clearance, creatinine clearance, and fractional excretion of sodium were calculated. The mean concentration of plasma myoglobin on the 1st day post-trauma was 3087 ng/ml. A continuous decrease in plasma myoglobin concentration could be observed, with a mean value of 497 ng/ml on day 7. The myoglobin concentration in urine showed marked fluctuations: the mean values were 3.37-4.12 mg/ml on day 1 and 0.78-1.34 mg/ml on day 7. There was no correlation between plasma and urine myoglobin concentrations. The myoglobin concentration increased during the period of observation, but there was no correlation with the creatinine clearance. The fractional excretion of myoglobin was in the range of 1% to 14%. There was no correlation between the fractional excretions of myoglobin and sodium.(ABSTRACT TRUNCATED AT 250 WORDS)