Metabolism of Vitamin D in Animals

Abstract

In the foregoing papers, the authors have reported the decrease of sulfate meta bolism in vitamin D-deficient chicks (1), the participation of vitamin D3 in active sulfate metabolism of chicks (2), the biogenesis of vitamin D sulfate in animal tissues (3) and the distribution and isolation of vitamin D selfokinase in animal tissues (3). Further researches were made on the physicochemical and biological properties of pure synthetic vitamin D2 sulfate.Its identification and estimation were also made by means of antimony trichloride reaction, thin-layer chromatography and spectrophotometry.The authors first tested the occurence of water-soluble vitamin D sulfate in fresh cow's milk and found to be always positive. Further, its presence in human milk was studied, and found that there is a remarkable amount of the componnd. EXPERIMENTAL AND RESULTS Tests for the Presence o f Vitamin D Sulfate in Fresh Cow's MilkOne part of fresh cow's milk was evaporated under reduced pressure to a one-third part.To one part of the latter was added three parts of ethanol and the precipitate chiefly consisting of crude protein was removed by filtration. The filtrate was tested for the presence of vitamin D sulfate.After removal of the solvent, the residue was again dissolved in butanol or chloroform , and the solution was tested for the presence of vitamin D sulfate . The analysis was carried out using Libermann's reaction , antimony trichloride reaction and thin-layer chromato graphy.In the parallel experiments , the same compound in commercial non-processed evaporated milk and powdered milk was estimated . The results were quite similar.

The total content of vitamin D in human milk and cow's milk

“…These values must be assumed to correspond to the amount contained in the lipid fraction of milk. However, Sahashi et al (1967) have isolated water-soluble vitamin D from cow's milk and from human milk in quantities corresponding to much higher values, i.e. in cow's milk 204 i.u./l in addition to 36 i.u./l in fat-soluble form, while in human milk the concentration corresponded to 950 and 15-7 i.u./l.…”

“…in cow's milk 204 i.u./l in addition to 36 i.u./l in fat-soluble form, while in human milk the concentration corresponded to 950 and 15-7 i.u./l. In a subsequent work (Sahashi et al 1969) the authors have determined the biological activity.…”

Vitamin D: An Update

“…Sahashi et al (102) found the concentration of D-sulfate in cow milk and human milk to be 204 and 950 IU/liter (5 and 24 ng/ml), respectively. The D-sulfate concentration was 17.8 ng/ml between the 3rd and 5th days and 10.0 ng/ml between the 6th and 8th days, respectively.…”

Antirachitic Potency of Vitamin D Sulfate in Human Milk

“…Biochemistry and Nutrition , In the forgoing papers, the authors have reported the relation between vitamin D and active sulfate metabolism (1)(2)(3)(4), and the isolation of vitamin D sulfate from mammalian milk (5). Further tests for the antirachitic potency of human milk (containing 780I.U.…”