Abstract
From the results of viatmin A assay on rats according to the method described in U.S.P. XIV it was found that xenyl- and β-naphthyl-vitamin A urethane had an A-action, though less than standard A palmitate, while A-polyethyleneglycolether had almost no such action. Addition of vitamin D_2 to the sample gave a good result to the growth of rats as R.Takata and others claimed. The less effectiveness of the A-urethane compounds seemed to reresponsible to their smaller oilaffinity than A palmitate. Further studies are necessary to make clear their units, mechanism of absorption and split of the urethane by enzyme.
