Effect of Oral Administration of Vitamin K₁ or K₂ on Alkaline Phosphatase Activity in Rats

Abstract

Alkaline phosphatase (ALP) hydrolyzes a variety of monophosphate esters into inorganic acid and alcohol at a high optimum pH (pH 8-10) . Intestinal ALP activity is known to be increased by oil administration, but little is known about its physiological function. In the present study, we examined the effect of oral administration of vitamin K₁ or K₂ on alkaline phosphatase activity in rats. Male Sprague Dawley rats were orally administered 0.2 mL of a solution of PK (PK group) or MK-4 (MK group) . Just before (0 hours) and after (1.5, 3.0, or 4.5 h) oral administration, we obtained samples from the intestine, liver, and kidney. It was found that in the PK and MK groups, the levels of ALP activity in the duodenum and upper ileum were increased significantly after oral administration. However, there were no significant differences in ALP-specific activities in the liver or kidney after oral administration of vitamin K. These results suggest that oral administration of PK and MK-4 induces intestinal ALP activity.