Effects of seasonal photoperiod on serum 25-hydroxycholecalciferol and calcium in reindeer, Rangifer tarandus tarandus.
In order to understand the effects of solar irradiance on calcium metabolism we measured serum 25-hydroxycholecalciferol and total calcium levels monthly in 6 female nonpregnant reindeer maintained in the Oulu area (65 degrees N). Mean monthly serum total calcium levels varied slightly and the highest levels were seen in October. Serum 25-hydroxycholecalciferol levels were highest in October but the monthly variation was also slight. The small monthly variation of the analytes' abundance and the fact that they peaked not until 4 months after the longest day, (i.e. the main stimulus for vitamin D synthesis) could have something to do with the supplementation of this vitamin in the diet of the captive reindeer.
Vierimaa
H
H
Department of Physiology, University of Oulu, Finland.
Timisjärvi
J
J
Eloranta
E
E
Saarela
S
S
Ruokonen
A
A
Leppäluoto
J
J
D000818:Animals; D002112:Calcifediol / Q000097:blood*; D002118:Calcium / Q000097:blood*; D005260:Female; D017440:Photoperiod; D012053:Reindeer / Q000502:physiology*; D012621:Seasons; D014466:Ultraviolet Rays
D002112:Calcifediol; D002118:Calcium