The interactions of iron with other divalent metals in the intestinal tract of a freshwater teleost, rainbow trout (Oncorhynchusmykiss).
This study examined the concentration-dependent interactive effects of four essential (Cu(2+), Zn(2+), Ni(2+), Co(2+)) and two non-essential (Pb(2+) and Cd(2+)) divalent metals on intestinal iron (Fe(2+)) absorption in freshwater rainbow trout (Oncorhynchusmykiss) using an invitro gut sac technique. All of the divalent metals except cobalt inhibited the intestinal Fe(2+) absorption in fish, and the magnitude of inhibition followed the order of: Ni(2+)~Pb(2+)>Cd(2+)~Cu(2+)>Zn(2+). The mucosal epithelium of the intestine was found to be the most sensitive to inhibition relative to the mucus or blood compartment, suggesting that these interactions likely occur via the divalent metal transporter-1 (DMT1). In addition, the reciprocal effects of Fe(2+) on intestinal accumulation of lead and cadmium were investigated. Elevated Fe(2+) did not affect lead accumulation in the intestine, indicating a greater affinity of Pb(2+) to the Fe(2+) transport pathway and/or the existence of additional pathways for lead absorption. In contrast, the accumulation of cadmium in the intestine decreased considerably in the presence of excess Fe(2+), indicating the importance of the Fe(2+) absorption pathway in dietary cadmium accumulation in fish. Overall, our study provides important insights into the mechanisms of dietary uptake of several divalent metals in freshwater fish.
Kwong
Raymond W M
RW
Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B3.
Niyogi
Som
S
D000818:Animals; D001692:Biological Transport; D002104:Cadmium / Q000378:metabolism; D027682:Cation Transport Proteins / Q000502:physiology; D002413:Cations, Divalent / Q000378:metabolism*; D003035:Cobalt / Q000378:metabolism; D003300:Copper / Q000378:metabolism; D005618:Fresh Water / Q000032:analysis*; D041981:Gastrointestinal Tract / Q000378:metabolism*; D007408:Intestinal Absorption / Q000187:drug effects; D007413:Intestinal Mucosa / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D007854:Lead / Q000378:metabolism; D009532:Nickel / Q000378:metabolism; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism; D000099236:Solute Carrier Family 11, Member 2
D002104:Cadmium; D027682:Cation Transport Proteins; D002413:Cations, Divalent; D003035:Cobalt; D003300:Copper; D007501:Iron; D007854:Lead; D009532:Nickel; D015032:Zinc; D000099236:Solute Carrier Family 11, Member 2