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Seaward migration of Salmo salar is preceded by preparatory physiological adaptations (parr-smolt transformation) to allow for a switch from freshwater (FW) to seawater (SW), which also means a switch in ambient calcium from hypocalcic (<1 mM Ca(2+)) to the plasma (~1.25 mM Ca(2+)) and to strongly hypercalcic (8-12 mM Ca(2+)). Uptake, storage (skeleton, scales) and excretion of calcium need careful regulation. In fish, the vitamin D endocrine system plays a rather enigmatic role in calcium physiology. Here, we give direct evidence for calcitriol involvement in SW migration. We report the full sequence of the nuclear vitamin D receptor (sVDR0) and two alternatively spliced variants resulting from intron retention (sVDR1 and sVDR2). In FW parr, SW adapting smolts, and in SW adults, plasma concentrations of 25(OH)D(3) and 24,25(OH)(2)D(3) did not change significantly. Plasma calcitriol concentrations were lowest in FW parr, doubled during smoltification and remained elevated in SW adults. Increased calcitriol coincided with a twofold decrease in sVDR mRNA levels in gill, intestine, and kidney of FW smolts and SW adults, when compared with parr. Clearly, there was a negative feedback and dynamic response of the vitamin D endocrine system during parr-smolt transformation. The onset of these dynamic changes in FW parr warrants a further search for the endocrines that initiate these changes. We speculate that the vitamin D system plays a crucial role in calcium and phosphorus handling in Atlantic salmon.
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
December 1973,
Life sciences,
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
December 1974,
Science (New York, N.Y.),
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
October 2011,
The Journal of biological chemistry,
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
March 2004,
Endocrine regulations,
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
April 2019,
Nutrients,
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
July 1975,
Biochemical and biophysical research communications,
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
December 1994,
Comparative biochemistry and physiology. Part A, Physiology,
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
August 2002,
Immunopharmacology and immunotoxicology,
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
April 1999,
Steroids,
E J Lock, and
R Ornsrud, and
L Aksnes, and
F A T Spanings, and
R Waagbø, and
G Flik
August 2008,
International journal of obesity (2005),
