Effects of fasting on distribution and excretion of lead following long-term lead exposure in rats.

Lead was given to rats through drinking water containing 100 ppm lead acetate for 20 days. Delta-aminolevulinic acid dehydratase (ALAD) activity in erythrocytes was significantly lower (p < 0.05) at 20 days after Pb treatment. Erythrocytic ALAD activity was significantly lower (p < 0.05) in fasted rats than in fed rats with or without Pb pretreatment. Serum glutamic pyruvic transaminase and glutamic oxaloacetic transaminase activities after 6 days of fasting were significantly higher (p < 0.05) in Pb pretreated rats than in other groups (Pb nontreated fed and fasted rats, and Pb pretreated fed rats). Long periods of fasting strongly enhanced these serum-enzymes elevations induced by lead. Maximum Pb concentrations and total amount in feces increased in rats fasted for 3 days regardless of Pb pretreatment. On the other hand, total amount of Pb in feces of rats fasted for 6 days were not significantly different from the other groups because their fecal volume decreased to about 1% of fed rats. The Pb concentrations of liver, kidney, spleen, and femur increased significantly in Pb pretreated rats compared to in controls, but there were no significant differences between the fed and fasted rats.