Three experiments were conducted on incorporation of urea nitrogen into body proteins. The first was to study the distribution of ¹⁵N in organs after ¹⁵N-urea administration, the second to estimate how much urea could be utilized for protein synthesis, and the third to clarify a nutritional role of urea nitrogen. Rats fed on low protein (5% casein) diet were used. The results were as follows;
1) The retention rates of ¹⁵N in the whole body, as shown in a percentage of administered ¹⁵N, were 25.34% in LPD (rats fed on low protein diet) group and only 5.26% in SPD (rats fed on standard protein diet) group. Among the organs, the carcass protein had the largest part of ¹⁵N retention.
2) ¹⁵N incorporation into plasma protein increased in proportion to the amouut of administered ¹⁵N-urea between 10 and 30mg/100g B.W. However, the efficiency of ¹⁵N utilization in protein synthesis was depressed over the range of 30mg/100g B.W. and reached the maximum at 50mg/100g B.W.
3) Growth curve of weanling rats fed on low protein diet supplemented with urea rose significantly by 50% from that of weanling rats fed on control (without supplementation).
Thus, it is concluded that urea nitrogen can be utilized for the synthesis of body protein in rats fed on low protein diet, inducing an increase in body weight. The maximum level of urea N bioutility existed so that the amount of urea supplementation should be proper.

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The effects of a restricted diet on protein metabolism were studied in rats made obese by a diet containing 30% fat. Three restricted diets, all containing 5% fat, were a high-protein diet (HPD; 50 % casein), a standard-protein diet (SPD; 25% casein), and a low-protein diet (LPD; 5% casein). The intake of feed was restricted to 5g per day. Two weeks later, every group of rats that had eaten one of the restricted diets lost about 100g in body weight; the level of protein intake made no difference in the weight decrease. The nitrogen balance of the HPD and SPD rats was positive; that of the LPD was strongly negative. The amount of moisture in the carcass in the restricted-diet groups was similar, but there were significant differences in the percentage of lipids and protein. The percentage of protein was the highest and that of lipids was the lowest in the carcasses of HPD rats.
These results suggest that the amount of protein in a restricted diet is important to maintain protein metabolism in obese rats.

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To investigate the mechanism responsible for the circadian variation of elimination processes of ethanol (EtOH), EtOH (100mg/100g B.W.) was orally administered to female Sprague-Dawley rats at 8: 00 and 20: 00 under non-fasting conditions, and EtOH concentration in plasma prepared from tail venous blood was determined with gaschromatograph at constant intervals. The intakes of feed and water 12 hours before oral administration of EtOH were also measured to elucidate the relationship between feed intake or water intake and each parameter obtained from the time course of plasma EtOH concentration (p [EtOH]). Immediately after EtOH was disappeared in Plasma, the rats were decapitated. Concentration of EtOH in stomach and the content in stomach for each rat were measured, and specific activity of alcohol dehydrogenase (ADH) in liver was determined spectrophotometrically at 37°C and pH 9. Solid feed and water were given to rats ad libitum during the light period (8: 00-20: 00) and the dark period (20: 00-8: 00). The feed intakes from 20: 00 to 8: 00 and from 8: 00 to 20: 00 were 5.7±1.6mg·g^-1 B.W. ·hr^-1 and 1.6±0.7mg·g^-1 B.W. ·hr^-1, respectively. The former was bigger than the latter. The water intake during the dark period was 2.2 times bigger than that during the light period. Therefore, the feed and water intakes during the dark period were higher than those during the light period. The max. p [EtOH] (A), the time to reach max. p [EtOH] (B), the time of pEtOH disappearance (C) and integration value of pEtOH (D) obtained from the dark period were 2.0, 1.5, 1.6 and 3.2 times bigger than those obtained from the light period, respectively. This means that there is the diurnal rhythm of the time course of p [EtOH]. Liver ADH activity showed nonsignificant change between the light period and the dark period. The remaining rates of EtOH in the stomach (= (Content of EtOH in stomach/total content of EtOH administered) ×100) were 25.8±10.7% for the light period, and 0.3±0.4% for the dark period, the former was 86 times higher than the latter. Therefore, A, B, C and D showed the diurnal variation under the non-fasting conditions. However, apparent decay rate constant (k) of EtOH showed no diurnal variation in both groups. There was bigh negative correlation (γ≅ -0.8) between each parameter (A, B, C and D) except k value and the remaining rate of EtOH in stomach. From these results, it is likely that the diurnal rhythm of p [EtOH] under non-fasting conditions is controlled by the remaining rate of EtOH in stomach and independent of the change of liver ADH activity.

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The concentration of 1-MTHBC, a precursor of harman, in several kinds of fermented seasonings commercially available in Japan was determined as a pentafluoropropionic acid derivative by gas chromatography with a flame thermionic detector and a capillary column. The contents of 1-MTHBC were 4-250ppm for soy sauce, 0.04-12ppm for mixed seasoning, 0.003-1.4ppm for miso and below 0.08ppm for vinegar. The correlations between the contents of 1-MTHBC and 1-MTHBC-3-carboxylic acid, ethanol or methanol in 23 brands of soy sauce were examined. As a result, a positive correlation between the contents of 1-MTHBC and methanol was found. To determine whether 1-MTHBC is originaliy present in soy sauce or is an artifact, 1-MTHBC in soy sauce was isolated by high performance liquid chromatography with an octadecyl silyl column and acidic aqueous solution/acetonitrile (1/1) as an eluant. It was canfirmed by mass spectrametry that 1-MTHBC detected in soy sauce was not an artifact.

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Ascorbate oxidase (AsA oxidase) [EC 1. 10. 3.3] was purified from the spores of Myrothecium verrucaria IAM 5063. To purify this enzyme, the extract from the spores was chromatographed on DEAESephadex A-50, Sepharase 6B and CM-Sephadex C-50. In this way, the refative activity of AsA oxidase was increased by as much as 700 times.
This AsA oxidase was capable of oxidizing L-ascorbic acid (L-AsA) to form dehydroascorbic acid. Its activity was maximal in the pH range af 6-7 at approximately 30°C. A kinetic study showed that, under these optimal conditions, the Km value of the reaction was 3.0mM. The molecular weight of the enzyme was found to be approximated at 380K, which is abaut 2 times that of AsA oxidase of vegetable origin.
The exclusive singularity of the present mold AsA oxidase toward L-AsA was noted as a distinct difference from vegetable. AsA oxidase.
Mold AsA oxidase was even inhibited by D-iso ascorbic acid. The mechanism of this inhibition was found to be non-competitive on the basis of a Lineweaver-Burk plot.
The addition of Cu²⁺ increased the activity of AsA oxidase by a factor of 5.7.
A sigmoidal relationship was observed between the Cu²⁺ concentration and AsA oxidase activity, indicating the enzyme to passibly be a kind of cupper-binding enzyme.

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Preventive effects of additives on the thermal oxidation of Tocopherol (Toc) in olive oil were observed in the order of gallic acid (GA) and thiodipropionic acid>cystine>homogentisinic acid>tryptophan. In this paper, preventive effects of GA on the thermal oxidation of Toc in Vegetable oils (soybean, corn, linseed, coconut and olive oils) and frying soybean oil under the condition for frying Chinese noodle were investigated. Vegetable oils with or without GA were heated in a glass tubes for AOM test at 180°C for 15, 30 and 45hr, respectively. Chinese noodles were fried at 180°C in soybean oil with or without 0.1% GA, stored at room temperature, and their oxidative stabilities were compared.
Preventive effects of GA on the thermal oxidation of Toc in each vegetable oil during heating were observed. The oxidative stabilities of vegetable oils were considerably increased by the addition of GA. On the other hand, the percentage of residual GA during heating was higher in the presence of Toc in ail than in the absence of Toc. Chinese noodles fried in oil containing GA could relatively resist the oxidation.

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Barley flour inner 75 and outer 25 were finely milled, and their approximate composition and dietary fiber contents were determined. Protective effects of the two kinds of barley flour on water-immersion-induced gastric stress ulcer of rats were examined. The results were as follows:
1. Barley flour inner 75 was richer in fat, ash and dietary fiber than wheat flour. Barley flour outer 25 was more abundant in protein, fat, ash and dietary fiber than barley flour inner 75.
2. Sprague-Dewley rats were fed on the diets containing 10% of barley flour for 14 days, fasted for 24hr, and then immersed in water at 23°C to the height of their xiphoid fox 21hr.
The inhibitory rates of gastric stress ulcer induced by the water immersion were 67.4% by the diets containing barley flour inner 75 and 47.4 % by those containing outer 25, rgspectively.

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The transit of soybean oil through the gastrointestinal tract was studied in rats fed 4% pectin diet in comparision with those fed 4% cellulose diet. The structural changes of the surface of the small intestinal mucosa were also observed by scanning electron microscopy.
1. The ratio of lipid content in the feces of rats fed 4% pectin diet was higher than that of rats fed 4% cellulose diet.
2. The apparent lipid ahsorption ratio of rats fed 4% pectin diet was lower than that of rats fed 4% cellulose diet.
3. Rats fed 4% pectin diet showed irregular arrangement of the small intestinal villi, especially abnormal structure at the top of the villi.

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[in Japanese]

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