In contrast to rodents no induction of renal P-glycoprotein by 1,25-dihydroxyvitamin D in sheep.
Reduction of ruminal, jejunal and hepatic P-glycoprotein expression by 25-hydroxyvitamin D.
Induction of cytochrome P450 3A only with 1,25-dihydroxyvitamin D treatment.
Drug–drug interactions caused by vitamin D metabolites cannot be excluded.