Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to waterborne Cu (22 μg/l) in moderately hard water for up to 28 days. Relative to control fish kept at background Cu levels (2 μg/l), Cu-preexposed fish displayed decreased uptake rates of waterborne Cu via the gills but not of dietary Cu via the gut during 48-h exposures to 64Cu-radiolabeled water and diet, respectively. At normal dietary and waterborne Cu levels, the uptake rates of dietary Cu into the whole body without the gut were 0.40-0.90 ng·g-1·h-1, >10-fold higher than uptake rates of waterborne Cu into the whole body without the gills, which were 0.02-0.07 ng·g-1·h-1. Previously Cu-exposed fish showed decreased new Cu accumulation in the gills, liver, and carcass during waterborne 64Cu exposures and in the liver during dietary 64Cu exposures. A 3-h gill Cu-binding assay showed downregulation of the putative high-affinity, low-capacity Cu transporters and upregulation of the low-affinity, high-capacity Cu transporters at the gills in Cu-preexposed fish. Exchangeable Cu pools in all the tissues were higher during dietary than during waterborne 64Cu exposures, and previous Cu exposure reduced waterborne exchangeable Cu pools in gill, liver, and carcass. Overall, these results suggest a quantitatively greater role for the dietary than for the waterborne route of Cu uptake, a key role for the gill in Cu homeostasis, and important roles for the liver and gut in the normal metabolism of Cu in fish.
|Original language||English (US)|
|Journal||American Journal of Physiology - Regulatory Integrative and Comparative Physiology|
|Issue number||1 52-1|
|State||Published - Aug 20 2002|
- Copper metabolism
- Copper preexposure
ASJC Scopus subject areas