Influence of low luminal cadmium-concentrations on transfer of water and cadmium in the rat small intestine in vitro.
The sensitivity of the small intestinal water transfer for cadmium (Cd) exposure and its longitudinal gradient were investigated in luminally perfused intestinal segments in vitro and in vivo. Proximal segments accumulated Cd to a higher extent and, in addition, were more sensitive to Cd exposure than distal segments. In the proximal small intestine Cd impairs the intestinal water transfer at concentrations between 0.1 and 1.0 mumol/l in vitro and 4 mumol Cd/l in vivo. In vitro the Cd transfer from the intestinal tissue into the serosal absorbate declined in parallel to the reduction of the water transfer. In proximal but not in distal segments the declining water transfer corresponded to the decreases in glucose transfer in response to Cd exposure. According to literature the Cd effect on intestinal water transfer may be mediated by interaction of Cd with the Na-glucose co-carrier or by inhibition of the oxidative phosphorylation. The involvement of both mechanisms may differ along the small intestine.
Schümann
K
K
Walther Straub-Institute of Pharmacology and Toxicology, München, F.R.G.
Elsenhans
B
B
Strugala
G
G
Hunder
G
G
D000818:Animals; D001834:Body Water / Q000378:metabolism*; D002104:Cadmium / Q000493:pharmacokinetics / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D007421:Intestine, Small / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
D002104:Cadmium; D005947:Glucose