Photosynthesis of vitamin D3 in cats
How, K.L.; Hazewinkel, H.A.; Mol, J.A.
Veterinary Record 134(15): 384
1994
ISSN/ISBN: 0042-4900 PMID: 8009805 Document Number: 423789
Two samples of skin were excised from each of 5 unmedicated, lightly pigmented adult cats and from 5 unmedicated research rats which had been killed. One sample from each animal was used to estimate the vitamin D precursor 7-dehydrocholesterol (7DHC) and vitamin D3 content while the other was irradiated with ultraviolet light between 290 and 315 nm (UV-B) and then examined for 7DHC and vitamin D3 content. The concentrations (per cmsuperscript 2) in unirradiated skin (mean +or- sd) were: 7DHC in cats 1958 +or- 456 ng and in rats 17 620 +or- 5244 ng; vitamin D3 in cats 193 +or- 39 ng and in rats 161 +or- 72 ng. The concentrations of vitamin D3 were not significantly different in irradiated cat skin, whereas an increase of 411 +or- 2888 ng vitamin D3 was found in rat skin. The results show that cats are not able to synthesise vitamin D3 effectively in their skin. Although a very efficient mechanism of synthesised vitamin D3 utilisation cannot be ruled out, the determination and supplementation of the optimal amount of vitamin D for cats is important.