Uptake and tissue distribution of chromium(III) in mice after a single intraperitoneal or subcutaneous administration.

The tissue levels of chromium were followed after single intraperitoneal or subcutaneous injection of 1 mmol CrCl3/kg body wt. in Swiss male mice. Blood levels were similar after both treatment modes, with half-lives of 31-41 h. Organs not directly exposed by i.p. treatment contained similar amounts in the two groups, with kidneys > lungs > heart > brain. However, after i.p. treatment peritoneal organs (liver, spleen, pancreas and testis) had 40- to 200-fold more chromium compared with s.c. Assay of subsurface liver tissue and of testes removed via the scrotum indicated infiltration of the organs, rather than surface adsorption, of peritoneal chromium. Relative chromium concentrations after i.p. treatment were liver > pancreas = spleen > testis and after s.c. liver > spleen > testis > pancreas. Thus, s.c. treatment with CrCl3 is as effective as i.p. in terms of absorption into the blood. Treatment i.p., leading to direct uptake into peritoneal organs, is an effective way to deliver high chromium doses to these organs, but does not model likely human exposure.