The effect of riboflavin deficiency on in vivo incorporation of [1-¹⁴C] leucine into proteins of liver has been studied on rats following protein depletion and subsequent repletion.
The increase in the incorporation of [¹⁴C] amino acid into liver proteins following protein depletion was less marked in riboflavin-deficient rats. But repletion with 40% protein demonstrated marked diminished protein incorporation in riboflavin-deficient rats compared to pair-fed control rats.
Riboflavin deficiency does not show any alteration in the liver protein concentration following any of the dietary treatments.
It is concluded that there occurs less synthesis and diminished rate of breakdown of liver proteins in riboflavin deficiency following protein depletion, and repletion with high protein diet following protein depletion causes diminished protein synthesis as well as reduced protein breakdown in liver of riboflavin-deficient rats and consequently liver protein concentration remains unchanged.

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Determination of potential vitamin D₂ (the sum of vitamin D₂ and pre-D₂) in UV irradiated products of ergosterol was investigated by a GLC method. Both vitamin D₂ and pre-D₂ were quantitatively isomerized into the thermal cyclized products “pyro- and isopyro-D₂” by GLC. It was previously reported that the separation of pyro-D₂ from lumisterol₂ was difficult (6, 7), but their separation has been found to be successfully achieved by applying the TMS ethers of samples to the GLC using the following apparatus and analytical conditions: apparatus, a Shimadzu GC-4APTF gas chromatograph equipped with a hydrogen flame ionization detector; column, a glass column (0.4×150cm) packed with 1.5% OV-17 on Shimalite W (80-100 mesh); column temperature, 215°; flow rate of nitrogen gas, 80ml/min. Recovery tests of vitamin D₂ in the mixtures of vitamin D₂ isomers by the GLC gave good results, and no special inhibitory peak was observed in the gas chromatogram of irradiated ergosterol products. From these results, the GLC procedure applicating the operating parameters mentioned above after trimethylsilylation of samples and using the peaks of pyro-D₂ TMS ether and stigmasteryl acetate as an internal standard was established as a routine method for the determination of potential vitamin D₂ in irradiated ergosterol products.
The effects of ergosterol concentrations, temperatures, solvents, use of a filter solution and light sources on the yield of potential vitamin D₂ were examined by using this method. The effects of light sources and ergosterol concentrations were large, whereas the other conditions gave little effects.

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The hydrogen peroxide (H₂O₂) hemolysis test has been widely used as an index of vitamin E deficiency in animals and humans. In the present study, the relationship between the degree of H₂O₂ hemolysis and serum vitamin E level was investigated in adult patients with anemia due to various etiologies. H₂O₂ hemolysis values were found to be abnormally elevated in 4 cases of hereditary spherocytosis, 11 of 40 cases of iron deficiency anemia, 2 of 10 cases of anemia due to renal insufficiency and 1 of 5 cases of anemia due to infection. The elevation of H₂O₂ hemolysis in cases of anemia due to renal insufficiency or infection was not related to the decrease of serum vitamin E level. However, mean serum vitamin E levels in cases of hereditary spherocytosis and iron deficiency anemia were statistically lower than those of healthy adults. These experiments suggest that low serum vitamin E levels in cases of hereditary spherocytosis and iron deficiency anemia play some role in the cause of fragility of the red blood cells in these anemias.

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The agar-plate diffusion method for determination of vitamin B₆ in natural products was presented, which improved on its weak point of relative insensitivity by using a thin-layer plate technique.
The optimum conditions for the assay were proposed as follows. Assay medium: Atkin's basal medium with minor modifications and 1% agar, 0.75mm plate thickness (thin-layer), pH 5.0 to 6.0. Standard solutions of vitamin B₆: pH 5.0 to 6.0. Inoculum size of test organism: 0.075 optical density in final. Incubation: 30°, 12 to 16 hr.
Under our conditions a reproducible, clear and sharply-defined growth zone on the assay plate was steadily obtained and there was a linearity of the dose-response to pure vitamin B₆ solution over a wide range of 20 to 2, 000mμg/ml. In the statistical analysis of the results the probable errors amounted to only 4 to 5%. The total vitamin B₆ values in some natural materials obtained by this method were as equal as those determined with turbidimetric ones. Also, recovery experiments were successful enough and the dose-response line for all samples used hardly had any drift from that for pure vitamin B₆ solution.
This method is simple, accurate and adequate for the routine assay of a large number of samples.

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Fast acting sterols observed by Liebermann reaction, which mainly contain Δ⁷-sterol analogue, 7-dehydrocholesterol, were significantly increased 3 hours after an oral administration of vitamin D₃ in the vitamin D deficient rat liver.
The decrease of Δ^{5, 7}-sterol-Δ⁷-reductase [E.C. 1.14.1] activity was also observed by vitamin D₃ treatment. While NADPH level was not affected, NADP⁺ level was decreased by vitamin D₃ administration. Using gel filtration technique it was demonstrated that 7-dehydrocholesterol-³H bound to an activator protein of Δ^{5, 7}-sterol-Δ⁷-reductase both in vivo and in vitro and that this binding of 7-dehydrocholesterol-³H was suppressed by vitamin D₃. Vitamin D₃-³H was also bound to the activator protein.
From these results, it was shown that vitamin D₃ inhibited the conversion of 7-dehydrocholesterol to cholesterol. And the decrease in the binding of 7-dehydrocholesterol-³H to an activator protein by vitamin D₃ will suggest that vitamin D₃ binds to the activator protein in place of 7-dehydrocholesterol.

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The chick urinary metabolites of chloroethylthiamine, a potent coccidiostat, were studied. After 20mg of ³⁵S-chloroethylthiamine was administered to chicks, 17 radioactive metabolites were separated by Amberlite CG-50 column chromatography followed by cellulose thin layer chromatography. Five major metabolites were identified to be unchanged chloroethylthiamine, thiamine, thiamine anhydride, thiamine anhydride sulfoxide and thiamine anhydride sulfone. The amounts were 34.2, 3.3, 18.3, 4.9 and 4.1% of the total urinary radioactivity, respectively. After intraperitoneal administration of ³⁵S-chloroethylthiamine, however, the formation of thiamine was negligible. These results suggest that the gastrointestinal tissue or the intestinal flora might play an important role in the biotransformation of chloroethylthiamine to thiamine. It was indicated that the stimulative effect of chloroethylthiamine on chick growth is due to the formation of thiamine.

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β-Ketovinyl thioether type thiamines and the related compounds have been examined on thiamine activity as well as thiamine liberation in vitro and in vivo. Sixteen compounds showed more or less vitamin activity, of which the most active ones were BD 108 and BD 81 with about 70% of the activity of thiamine HCI, while BD 101 and BD 142 showed no activity. BD 99, BD 108, and BD 112 with higher thiamine activity were converted into thiamine by incubation with glutathione. Urinary excretions of thiamine was significantly increased following intraperitoneal injection of these derivatives. A correlation was recognized between thiamine activity and urinary excretion of thiamine.

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