Changes of glucose metabolism and skin-collagen neogenesis in vitamin B_{6} deficiency

Article type: Research Article

Authors: Inubushi, Tomoko | Takasawa, Tomohiro | Tuboi, Yasue | Watanabe, Naoko | Aki, Kenji | Katunuma, Nobuhiko

Affiliations: Tokushima Bunri University, Faculty of Life Science, Tokushima 770-8514, Japan | Tokushima Bunri University, Institute for Health Sciences, Tokushima 770-8514, Japan

Note: [] Address for correspondence: Tokushima Bunri University, Yamashiro-cho, Tokushima City 770-8514, Japan. Tel.: +81 88 622 9611; Fax: +81 88 622 3217; E-mail: inutomo7@tokushima.bunri-u.ac.jp

Abstract: The mechanism of pellagrous changes in skin caused by a deficiency of vitamin B_{6} was studied in respect to neogenesis of proline in skin collagen and glucose metabolism. In vitamin B_{6} deficiency the insulin/glucagon coefficient in serum decreased significantly from 3.02 to 2.32, indicating a metabolic change towards gluconeogenesis. A deficiency of vitamin B_{6} caused a decrease in the levels of vitamin B_{6}-dependent enzymes, such as ornithine aminotransferase, alanine aminotransferase, and aspartate aminotransferase, which also contribute to gluconeogenesis. Because the conversion of ornithine to proline via pyrroline-5-carboxylate was suppressed due to the decrease in ornithine aminotransferase activity, the amount of proline in the skin collagen fraction also decreased significantly in vitamin B_{6}-deficient rats compared with the pair-fed control. These results suggest that the pellagrous lesions in vitamin_{6}-deficiency are caused by an impaired synthesis of proline from ornithine, which results in the suppression of collagen neogenesis in the skin.

Keywords: Vitamin B[TeX:] _{6} deficiency, insulin, ornithine aminotransferase, skin collagen

Journal: BioFactors, vol. 23, no. 2, pp. 59-67, 2005