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Plasma concentrations of vitamin D3 (cholecalciferol) metabolites have been studied in rainbow trout (Salmo gairdneri) adapted to varying environmental calcium concentrations in both fresh water and artificial seawater, and in natural seawater. In vivo, intraarterial injection of tritiated 25-hydroxycholecalciferol was followed by its transformation to a number of metabolites including compounds that cochromatographed on high performance liquid chromatography (HPLC) with 1,25-dihydroxycholecalciferol and 25,26-dihydroxycholecalciferol. Hypercalcaemia and increased environmental calcium were associated with a greater transformation to the compound cochromatographing with 25,26-dihydroxycholecalciferol, while hypocalcaemia and reduced environmental calcium concentrations induced more conversion to the 1,25-dihydroxycholecalciferol-like compound. In vitro, both metabolites were produced by liver but not by kidney preparations, and the difference in conversion ratios observed in vivo associated with changes in plasma calcium were also seen in vitro. It is concluded that the metabolism of 25-hydroxycholecalciferol in the trout can be influenced by calcium status, but at present the physiological importance of this metabolism and the mechanisms and site(s) of action of the metabolites are unknown.
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
November 1982,
The Journal of nutrition,
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
January 1984,
Developmental and comparative immunology,
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
October 1974,
Bulletin of environmental contamination and toxicology,
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
June 1983,
General and comparative endocrinology,
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
December 1979,
Ecotoxicology and environmental safety,
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
January 1966,
Bulletin - Office international des epizooties,
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
July 1983,
Revue canadienne de biologie experimentale,
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
January 1989,
Brain, behavior and evolution,
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
October 1969,
Experientia,
M E Hayes, and
D F Guilland-Cumming, and
R G Russell, and
I W Henderson
January 1976,
Progress in experimental tumor research,
