Beta-carotene uptake and bioconversion to retinol differ between human melanocytes and keratinocytes.

Division of Dermatology, Department of Biomedicine and Surgery, Clinical Research Center, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
Nutrition and Cancer (Impact Factor: 2.47). 02/2001; 39(2):300-6. DOI: 10.1207/S15327914nc392_21
Source: PubMed

ABSTRACT beta-Carotene is one of the carotenoids that has been considered to play a role in the natural defense against ultraviolet-induced skin cancer. It is not known whether epidermal cells are able to accumulate beta-carotene and, subsequently, convert it to vitamin A. We used normal cultured human keratinocytes and melanocytes to study the uptake, and possible bioconversion to retinol, of authentic or [14C]beta-carotene. The uptake was much higher in melanocytes than in keratinocytes, corresponding to a fivefold difference in the intracellular fraction after two days of incubation. An increased level of cellular retinol was noted after one day of beta-carotene incubation. The conversion of [14C]beta-carotene to [14C]retinol peaked at 24 hours of incubation in keratinocytes and melanocytes. The results suggest that beta-carotene can function as a local supply of vitamin A in the skin and that melanocytes are especially likely to store beta-carotene.

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