摘要：Urinary excertion of N-acetyl-β-D-glucosaminidase (NAG) is regarded as the most sensitive indicator of renal damage caused by occupational exposure to lead. In order to clarify the increase of NAG excretion caused by damage to the proximal renal tubule, we compared NAG isoenzyme patterns between a group of 17 male office workers and a group of 15 male lead-exposed workers using the electrofocusing-MCP-NAG method. Blood levels of lead (PbB) in the office workers and the lead exposed workers were 9.7±3.1 and 64.9±9.8μg/100g blood (mean±S. D.), respectively. All the means of the total NAG, NAG-A and NAG-B activity of the lead-exposed workers (5.7±4.9, 4.6±4.1, 1.1±0.8U/g creatinine, respectively) were significantly higher than those of the office workers (2.8±1.4, 2.2±1.0, 0.6±0.4U/g creatinine, respectively). But no difference was observed in the mean percentages of the isoenzymes (NAG-A and NAG-B) between the two groups. Since we found a significant increase in NAG excretion, but failed to find that the excess excretion was mainly due to NAG-B, there remained the possibilities that the lead exposure damaged the proximal renal tubular cell only very slightly, or stimulated the exocytosis of NAG, or stimulated renal activity of NAG.
