Pyridoxine and pyridoxine glucoside are transported into rabbit erythrocytes in vitro. The amounts of vitamin B₆ compounds transported into the erythrocytes were bioassayed with Saccharomyces carlsbergensis 4228 ATCC 9080 after hydrolyzing them to free forms of vitamin B₆ by autoclaving for 210min in 1/12 N sulfuric acid. The transport of pyridoxine and pyridoxine glucoside was affected by incubation time, incubation temperature and concentration of pyridoxine and pyridoxine glucoside added. The transport of pyridoxine glucoside iincreased with the coexistense of ATP or glucose. The transport of pyridoxine and pyridoxine glucoside decreased by the addition of sodium fluoride or monoodoacetate. The binding of pyridoxine and pyridoxine glucoside by ghost cells was not found. Small amounts of transported pyridoxine and pyridoxine glucoside were leaked out by washings, indicating that large parts of them were retained in the erythrocytes.

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The formation of pyridoxal phosphate in vivo has been studied in rats receiving high-fat diet. High-fat diet reduced the concentration of pyridoxal phosphate and the activity of pyridoxine phosphate oxidase in liver and kidney. Intraperitoneal administration of FMN to rats receiving high-fat diet restored the normal activity of pyridoxine phosphate oxidase, and consequently the functional level of pyridoxal phosphate in each of the tissues was maintained. The restoration in the activity of pyridoxine phosphate oxidase and in the level of pyridoxal phosphate was found to be dependent on adrenal corticoids in case of liver and on testosterone in case of kidney. It has been suggested that the cortisone and testosterone stabilise the pyridoxine phosphate oxidase of liver and kidney, respectively, by facilitating the binding of FMN with the apoenzyme.

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A new staining method for flavin-containing oxidases in the polyacrylamide gel was investigated. This method is based on the formation of red-colored dye, oxidized o-dianisidine, which is produced by the reaction of peroxidase (EC 1.11.1.7; donor: H₂O₂ oxidoreductase) coupling with a H₂O₂-producing oxidase in the presence of appropriate substrate. In comparison with the usual proteinstaining method, good results on the activity bands concerned were obtained from the investigation of glucose oxidase (EC 1.1.3.4; β-D-glucose: O₂ oxidoreductase), xanthine oxidase (EC 1.2.3.2; xanthine: O₂ oxidoreductase) and D-amino acid oxidase (EC 1.4.3.3; D-amino acid: O₂ oxidoreductase (deaminating)), and some findings were made by using this technique:
1. Commercial xanthine oxidase from buttermilk was separated into two bands which were both active in the presence of hypoxanthine.
2. Crystalline D-amino acid oxidase suspended in 1.8M ammonium sulfate showed distinct two bands.
3. Apoenzyme of glucose oxidase could be stained by pretreating with FAD solution prior to staining for the holoenzyme.

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The conversion of tryptophan to niacin in male albino rats fed different high fat diets was studied. While high fat diets were found to suppress the conversion of tryptophan to niacin, the effect was more pronounced in rats fed saturated fats than those kept on unsaturated ones. Saturated fats were observed to decrease, on long term feeding, the urinary and tissue levels of niacin to a greater extent than unsaturated fats. Supplementation of linoleic acid to hydrogenated fat restored niacin status to some extent, as compared with rats fed saturated fats alone.

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By systemic administration of vitamin E, studies were made to see whether dextran edema in rabbits and histamine and acetylcholine reactions in human can be depressed. Also, whether its topical administration can attain the suppression of croton oil dermatitis in rabbits and human plaster dermatitis was examined. It was found that vitamin E had antiinflammatory action, especially an action to suppress the enlargement and severity of the inflammation. The effect of such action of vitamin E was thought to be due to inhibition action of vitamin E on liberation and production of chemical mediators, as a result of stabilization action of vitamin E on the membranes although some reservations have been made on the supporting factor that vitamin E may contribute to antispreading factor and suppressive action on acceleration of capillary permeability.

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A new flavin was found in the culture medium of Schizophyllum commune, a Basidiomycete. The flavin was converted from riboflavin in a good yield. Some relationship between the flavin and L-malate production was observed.
This result supplys evidence that there are, at least, three different metabolic pathways of riboflavin among the three classes, Ascomycetes, Phycomycetes and Basidiomycetes.

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The incorporation of acetate-1-¹⁴C into lipid fractions in baker's yeast, Saccharomyces cerevisiae, grown in pantothenate-deficient (10μg/liter) medium, has been compared with that of the vitamin-sufficient (200μg/liter) yeast. In the vitamin-deficient yeast (I) acetate-1-¹⁴C was incorporated mainly into unsaturated fatty acids e. g. C_16:1, C_18:1, whereas in the vitamin-sufficient yeast it was incorporated mainly into saturated fatty acids e. g. C_16:0, C_18:0, (II) the incorporation of acetate-1-¹⁴C into sterol and triglyceride decreased and the level of free ¹⁴C-fatty acid was relatively higher than that in the vitamin-sufficient yeast. ³²P-Phospholipid in yeast grown in medium containing ³²P-phosphate was analyzed. In pantothenate-deficient yeast at the exponential phase, ³²P-phosphatidyl choline and ³²P-phosphatidyl ethanolamine were reduced one fourth and one third, respectively, of those in the vitamin-sufficient yeast. In pantothenatedeficient yeast much of oleic acid was found at the 2-position of phosphatidyl choline and at the 1- and 2-positions of phosphatidyl ethanolamine.

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In order to elucidate the mechanism of the anticoccidial action of chloro-ethylthiamine, the effect of chloroethylthiamine on the biological systems related to thiamine was examined. Chloroethylthiamine did not influence the activity of thiamine pyrophosphokinase (EC 2.7.6.2) from rat livers and Ehrlich ascites carcinoma cells and also the coenzyme activity of TDP on pyruvate decarboxylase (EC 4.1.1.1) and transketolase (EC 2.2.1.1.) from baker's yeast. On the other hand, chloroethylthiamine exhibited a marked inhibition against thiamine transport mediated by a carrier through biological membranes in Ehrlich ascites carcinoma cells or chick small intestine.
The inhibition of thiamine transport is an exclusive factor for the antithiamine action of chloroethylthiamine detected, indicating that this effect could be responsible for the exertion of the anticoccidial action. In fact, thiamine analogues which exert the anticoccidial action inhibited active transport of thiamine by the small intestine of rats and those which did not depress thiamine transport could not exert any anticoccidial action. These results lead to the conclusion that the anticoccidial action of chloroethylthiamine is due to its ability to inhibit thiamine uptake by the coccidium, Eimeria tenella.

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Anti-potassium, anti-quinidine, and anti-acetylcholine effects of thiamine tetrahydrofurfuryldisulfide (TTFD) on isolated guinea-pig atria were compared with those of thialium, dimethialium, dimethiamine propyldisulfide (DMPD), oxythiamine, and oxythiamine propyldisulfide (OTPD). From the different effects of these thiamine derivatives having different chemical structures, the following findings were obtained in relation to their possible active atom groups in above effects.
1) TTFD and DMPD showed an anti-potassium effect on the spontaneous contractions; this action may be caused by atom groups common to their chemical structures, that is, the presence of an S-S bond and presumedly also of a pair of nitrogen atoms, one of which is in a 4-amino group in a pyrimidine ring and the other of which is in an open thiazole ring at a distance of about 4 ångström from the first.
2) TTFD and DMPD showed an anti-quinidine effect on the atrial contractions.
3) In its high concentrations, DMPD depressed the sino-atrial node activity.
4) The anti-acetylcholine effect of thiamine related compounds tested may be due to the fact that they have neither an S-S bond nor an amino group in their pyrimidine rings.
5) The anti-potassium, anti-quinidine effects of thiamine were weak, while those of the thiamine derivatives such as TTFD and DMPD were remarkable because of the presence of an S-S bond which may promote an affinity of the thiamine molecule for atria.

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