Plasma 25-Hydroxyvitamin D₃ Response to a Pharmacological Dose of Vitamin D₃ or 25-Hydroxyvitamin D₃ during Chronic Ethanol Administration in the Rat

Summary

Plasma 25-(OH)D₃ concentrations following an intra-portal injection of 100 μg Kg^-1 of D₃ or 100 μg Kg^-1 of 25(OH)D₃ was studied in D depleted rats fed an ethanol diet and pairfed controls. When challenged with D₃, the rats under ethanol feeding were unable to increase their plasma 25(OH)D₃ concentrations above those observed in controls. Plasma 25(OH)D₃ concentrations following 25(OH)D₃ administration were however lowered by the ethanol treatment 3 and 96 hr after 25(OH)D₃ administration (p<0.05). These results suggest that animals chronically exposed to ethanol have an unaltered plasma 25(OH)D₃ response following a pharmacological dose of D₃ while the drug treatment contributes to an accelerated plasma 25(OH)D₃ disappearance following 25(OH)D₃. The former observations also suggest that D₃ does not seem to be a high affinity substrate for the ethanol-induced cytochrome P-450.

Key-Words:

Vitamin D ₃ - 25(OH)D ₃ - ethanol-cytochrome P-450 - liver metabolism