Tissue distribution and retention of cadmium in rats during postnatal development: minimal role of hepatic metallothionein
Wong, K.L.; Klaassen, C.D.
Toxicology and Applied Pharmacology 53(2): 343-353
1980
ISSN/ISBN: 0041-008X PMID: 7394775 Document Number: 161432
Since liver concentration of metallothionein in 4-day-old rats is 20 times greater than that in 70-day-old adults, experiments were performed to determine whether the high concentration of metallothionein in the liver of newborn rats results in a greater distribution of Cd to the liver and in subsequent lower concentrations of Cd in other tissues of the newborn in comparison to the adult, and if the retention of Cd in the various tissues is affected. The concentration of Cd in the liver of 4-day-old rats was only 30% higher than that in adult rats 2 h after administration (1 mg/kg, i.v.). Although there is no age difference in the renal concentration of metallothionein, the initial concentration of Cd in the kidney of 4-day-old rats was 1/2 that in adult rats. Cd was 3-6 times more concentrated 2 h after Cd administration, in the spleen, bone, brain, testes and muscle of newborn than in adult rats. Over a 19-day period, Cd was similarly retained in the liver, kidney and lung of newborn and adult rats, but the rate of Cd elimination was higher from the heart and lower from the testes of newborn rats when compared to adults. Metallothionein does not appear to play a major role in the tissue distribution and retention of Cd. The higher concentration of Cd in some target organs, such as testes, kidneys and lungs, of the newborn rat may have significant toxicological implications.