Studies on urinary proteoglycan excretion in occupational cadmium exposure

Six foundrymen occupationally exposed to cadmium fumes excreted in random urine samples 4.8 +/- 2.9 micrograms cadmium/g creatinine (+/- S.D.). Six controls excreted 0.15 +/- 0.09 microgram/g creatinine (+/- S.D.). The excretion of glycosaminoglycans by exposed men (2.3 +/- 1.1 mg/mmol creatinine, +/- S.D.) did not differ from that of controls (2.3 +/- 1.6 mg/mmol, +/- S.D.). However, electrophoretic analysis of the isolated urinary proteoglycan fraction revealed a dose-dependent progressive increase in the intensity of two bands with a molecular weight between 45,000 and 50,000. In control urines and in samples with urinary cadmium less than 3 micrograms/g creatinine, only one major band with a molecular weight of 100,000 was detected. The changes may serve as early indicators of the harmful effects of cadmium on the proteoglycan-containing barriers of the nephron.