Utilization, metabolism, significance and application of vitamin A in the dog and cat

In the plasma of carnivores vitamin A is transported in a retinol binding p rotein (RBP) and as retinylesters (retinylpalmitate, -stearate) in lipoprot eins of very low (VLDL) and low density (LDL). The concentration of retinyl esters in the lipoproteins is influenced by the intake of vitamin A. Biolog ical active metabolites of vitamin A are retinal, all-trans- and 9-cis-reti noic acid. The retinoic acids are bound to receptors and regulate the trans cription of more than 300 genes. Hypervitaminosis A in cats causes deformin g cervical spondylosis. Vitamin A is applied in combination with the vitami ns C, D and E for the stimulation of growth, of the activity of the immune system, of reproduction and of wound healing. Vitamin A and retinoids are u sed for the treatment of eye and skin diseases and of neoplasia of the skin in dogs.