Non-specific effects of aquaMEPHYTON (vitamin K1) on prothrombin expression in human hepatoblastoma (HepG2) cells.

In order to determine the effects of vitamin K1 on prothrombin production, we have treated cultures of human hepatoblastoma cells with an aqueous colloidal suspension of vitamin K1. Dose-response analysis demonstrated increases in secreted prothrombin antigen levels ranging from 3 to 3.7-fold over controls. Time-course analysis demonstrated increases in secreted prothrombin antigen levels over controls up to 6 hours of treatment. Between 6 and 24 hours, secreted prothrombin antigen levels increased at a rate parallel to controls. Vitamin K1 treatment also resulted in a parallel increase in total secreted protein levels. Prothrombin mRNA size (approximately 2.1 kb) and levels (ranging from 390-480 prothrombin mRNA molecules per cell) were determined by Northern and quantitative solution hybridization analysis, respectively, and were unaffected by vitamin K1 treatment. The increases in secreted prothrombin antigen levels most likely result from non-specific effects of vitamin K1 or agents used to emulsify vitamin K1 on protein release from HepG2 cells.