CADMIUM ACCUMULATION IN LIVER AND KIDNEY OF MICE EXPOSED TO THE SAME WEEKLY CADMIUM DOSE CONTINUOUSLY OR ONCE A WEEK

Cd levels in blood, liver and kidney of female mice were measured afte r exposure to Cd as CdCl2 in the food, either continuously (CE group) throughout the week (300 mu g Cd/kg feed) or for 24 hr/wk (2100 pg Cd/ kg) for 5 wk (occasionally exposed, OE group). In a control group that received feed with Cd levels below the detection limit (<7 mu g/kg), Cd levels in blood, liver and kidneys were below the detection limit a fter the 5 wk of exposure. The weekly dose of Cd administered to the e xposed CE and OE groups was similar (approx. 400 mu g Cd/kg mice/wk). The OE group had a higher Cd level in blood and a higher fractional ac cumulation (% of dose) of Cd in the liver and kidneys compared with th e CE group. This indicates that the fractional Cd absorption in the ga strointestinal tract is higher when high Cd doses are ingested occasio nally than when low doses are ingested continuously, even if weekly do ses are the same. It is hypothesized that this difference in absorptio n could be due to Cd-induced unspecific damage to the intestinal mucos a, changes in tight-junction permeability caused by Cd, or to a satura tion of the Cd-binding capacity of the intestinal mucosa in mice expos ed to high Cd levels occasionally. (C) 1997 Elsevier Science Ltd.