出版社：National Institute of Occupational Safety and Health
摘要：An experimental study was carried out to clarify the relationships between lead exposure and the changes in nerve conduction velocities or in por-phyrin metabolism in rats. The rats in Groups A, B and C received intraperitoneal lead injections in respective doses of 0, 0.2 and 2.0 mg/kg of lead, once a week for 22 weeks. During the experiment, all rats grew normally, and there was no signi-ficant difference in the group mean body weights. Lead concentrations in the blood and organs increased in these groups as the lead dose increased. Significant changes in nerve function and in biochemical indices relating to porphyrin metabolism were observed only in Group C treated with 2.0 mg/kg of lead, and not in the other groups. In Group C, urinary coproporphyrin and free erythrocyte protoporphyrin increased from an early stage, 4-6th week, of the lead administration, and urinary δ-aminolevulinic acid increased from the 8th week. Slight but significant slowing of conduction velocity in motor nerves appeared from the 10th week, when the rats had received lead injection 9 times in total. The change in distal motor latency occurred from the 16th week. No functional change in sensory nerves was ob-served in this study.
