| Abstract |
Alkaline phosphatase (ALP) hydrolyzes several monophosphate esters. It has been suggested that intestinal ALP, localized in the small intestine, is associated with lipid metabolism, although its physiological function has remained elusive. In this study, we investigated the effect of vitamin K2 (menaquinone-4; MK-4) on ALP expression in Caco-2 cells, which differentiate into human intestinal epithelial-like cells. The cells were incubated for 14 days after confluency, and MK-4 was added at 1 μM or 10 μM. ALP activity in both of the MK-4-treated groups was significantly higher than in an untreated control group (0 μM). The intensity of human intestinal ALP gene expression in Caco-2 cells was also significantly higher in the 1 μM MK-4-treated group than in the untreated control group. This is the first reported study to have investigated intestinal ALP expression induced by vitamin K2 in human intestinal epithelial-like Caco-2 cells. These results will be useful for elucidating the novel physiological functions of vitamin K2 through regulation of human intestinal ALP activity.
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