Fractional clearances of low molecular weight proteins in lead workers.
Urinary alpha 1-microglobulin (alpha 1-m) and beta 2-microglobulin (beta 2-m) can be used as early indicators of renal tubular dysfunction. However, low levels of lead exposure cause an increase in urinary alpha 1-m, but not in urinary beta 2-m. In order to clarify the level of tubular dysfunction in early lead nephropathy, fractional clearances of alpha 1-m (FC-alpha 1-m) and beta 2-m (FC-beta 2-m), i.e., the ratios of these clearances to the creatinine clearance, were measured in 99 male lead workers. Blood urea nitrogen, serum creatinine, uric acid, and urinary creatinine and N-acetyl-beta-D-glucosaminidase activity were also measured to diagnose the presence of other renal dysfunction. The median of FC-alpha 1-m was 0.13% in the control group. The FC-alpha 1-m increased in lead workers with blood lead (B-Pb) levels above 20 micrograms/dl. The correlation of FC-alpha 1-m with urinary alpha 1-m was highly significant, but there was no correlation with serum alpha 1-m. The median of FC-beta 2-m was 0.065% in the control group. There was a correlation of FC-beta 2-m with FC-alpha 1-m, but there was no correlation with B-Pb, or with serum beta 2-m. These results suggest the following: There was a very low excretion rate of alpha 1-m and beta 2-m in both the control group and the lead exposed groups. The excretion rate of alpha 1-m was higher than that of beta 2-m.(ABSTRACT TRUNCATED AT 250 WORDS)
Konishi
Y
Y
Department of Preventive Medicine and Environmental Health, Osaka City University Medical School, Japan.
Endo
G
G
Kiyota
A
A
Horiguchi
S
S
D000328:Adult; D000368:Aged; D000510:Alpha-Globulins / Q000652:urine*; D006801:Humans; D007684:Kidney Tubules / Q000187:drug effects / Q000502:physiology; D007854:Lead / Q000097:blood / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D001613:beta 2-Microglobulin / Q000652:urine*
D000510:Alpha-Globulins; C016001:alpha-1-microglobulin; D001613:beta 2-Microglobulin; D007854:Lead