Defense mechanisms against cadmium toxicity II. Effects of pretreatment with a small oral dose of cadmium on absorption, distribution and excretion of cadmium after a large oral dose in mice.
Uptake of Cd2+ by the liver and kidney of female mice 24 hr after challenge with a large dose of Cd2+ (100 mg Cd2+/kg, p.o.) was greatly reduced by pretreatment with a small dose of the cation (15 mg Cd2+/kg, p.o.) at 24 hr (for liver) and at 6, 24 or 48 hr (for kidney) prior to the challenge dose. The hepatic concentration of Zn2+ tended to be increased by the Cd2+ challenge and was increased further by pretreatment. The renal concentration of Zn2+ was not influenced by Cd2+ administration. The retention rate of Cd2+ in the stomach and its contents 24 hr after the Cd2+ challenge was decreased by pretreatment. In addition, the excretion rate of Cd2+ into the feces 24 hr after the Cd2+ challenge was increased by pretreatment at 6 to 24 hr prior to the challenge dose. Consequently, the absorption rate of Cd2+ 24 hr after the Cd2+ challenge was markedly reduced by pretreatment at 24 hr prior to the challenge dose. The urinary and biliary excretion of Cd2+ was very low. The motility of the small intestine was stimulated 6 hr after a small dose of Cd2+, but returned to normal within 24 hr. The motility tended to be reduced 4 hr after the Cd2+ challenge, but conversely, it was facilitated at 24 hr. Pretreatment at 6 or 24 hr prior to the challenge dose prevented the reduction of the motility 4 hr after the Cd2+ challenge.
D000818:Animals; D002104:Cadmium / Q000378:metabolism / Q000494:pharmacology*; D002105:Cadmium Poisoning / Q000378:metabolism*; D004361:Drug Tolerance; D005243:Feces / Q000032:analysis; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects; D007408:Intestinal Absorption / Q000187:drug effects*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D014018:Tissue Distribution / Q000187:drug effects; D015032:Zinc / Q000378:metabolism
D002104:Cadmium; D015032:Zinc