Relationship between inhibition of erythrocyte pyrimidine 5'-nucleotidase activity and biological response for porphyrin metabolism in workers occupationally exposed to lead.
A rapid determination of erythrocyte pyrimidine 5'-nucleotidase (P5N) activity in lead workers was carried out using a high-performance liquid chromatograph (HPLC). The P5N activity had a good negative correlation with the concentration of lead in blood (PbB) ranging from 16 to 96 micrograms/dl (r = -0.82, n = 77). Further, the P5N was compared with other biological parameters: erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity, erythrocyte protoporphyrin (PROTO), urinary delta-aminolevulinic acid (ALA) and urinary coproporphyrin (COPRO). The correlation coefficients between P5N and ALAD, log PROTO, log ALA, and log COPRO were 0.59, -0.72, -0.65, and -0.61, respectively. On the other hand, the normal value of P5N obtained from 72 healthy subjects was 11.9 +/- 2.1 units; mumol uridine/h/g Hb (mean +/- SD), indicating that the lower limit of 95% confidence interval for normal P5N was about 8 units. When P5N was cut off at less than or equal to 8 units in 77 lead workers, the validity (sensitivity + specificity) for PbB greater than or equal to 40 micrograms/dl, PbB greater than or equal to 60 micrograms/dl, erythrocyte PROTO greater than or equal to 150 micrograms/dl RBC, urinary ALA greater than or equal to 6 mg/l, and urinary COPRO greater than or equal to 150 micrograms/l was 1.66, 1.76, 1.57, 1.68, and 1.60, respectively. From these results, it was confirmed that the erythrocyte P5N test is suitable for the biological monitoring of exposure to lead in a wide range, and its activity is useful in predicting the disturbance of porphyrin metabolism induced by lead.
Tomokuni
K
K
Department of Community Health Science, Saga Medical School, Japan.
Ichiba
M
M
Hirai
Y
Y
Hasegawa
T
T
Sugimoto
K
K
D015720:5'-Nucleotidase; D000328:Adult; D000622:Aminolevulinic Acid / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D004781:Environmental Exposure; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D007854:Lead / Q000009:adverse effects* / Q000097:blood; D008297:Male; D009708:Nucleotidases / Q000097:blood*; D000623:Porphobilinogen Synthase / Q000097:blood; D011166:Porphyrins / Q000378:metabolism*
D011166:Porphyrins; D007854:Lead; D000622:Aminolevulinic Acid; D009708:Nucleotidases; D015720:5'-Nucleotidase; D000623:Porphobilinogen Synthase