The hepatic and renal activities of ornithine aminotrans-ferase (OAT) [L-ornithine 2-oxoacid aminotransferase, EC 2.6.1.13] were determined in male and female rats given diet with or without pyridoxine. OAT activities were measured in the presence of pyridoxal phosphate. Diet without pyridoxine caused a decrease in hepatic OAT activity in males and no change in females and an increase in renal OAT activity in males and a decrease in females. The increased renal OAT activity in males was associated with increased immunochemically recognizable OAT, and was due to increased synthesis of OAT as shown by measurement of [³H]leucine incorporation in vivo. Thus OAT is regulated by nutritional conditions in different ways in liver and kidney.

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The growth requirement or growth-promoting effect of biotin-vitamers on bacteria and yeasts was investigated. Biotin, dethiobiotin and biocytin (N-ε-biotinyl-L-lysine) were shown to be required for growth in a number of bacteria and yeasts. The biological activity of dethiobiotin was relatively higher than that of biotin, but was negative for lactic acid bacteria. Biocytin had high activity for Bacillus subtilis (natto), Debaryomyces japonicus and Hansenula capsulata. The biotin activity of 7-keto-8-aminopelargonic and 7, 8-diaminopelargonic acids was low or negligible for bacteria but relatively high for yeasts such as the genera of Endomyces, Endomycopsis and Saccharomyces. Pimelic, pelargonic and pelargonylhydroxamic acids had no growth requirement for or growth-promoting effect on any of the bacteria or yeasts tested.

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The authors performed multiple regression analysis of hemoglobin values and the parameters related to iron dynamics. The subjects consisted of 37 farmers whose Hb, Ht, GB, SI, %-St, SFR and FEP was examined once a month for one year. 19.2% of the female farmers had anemia of which 73.8% was iron-deficiency anemia, 13.7 being latent iron deficiency. Hb, GB and FEP in males and SI, %-St, SFR, FEP in females revealed clear seasonal variations. Multiple correlation coefficient between Hb and SI, %-St, SFR, FEP as independent variables was significant in females but not in males, and the ratio of contribution (38.7%) was not very high, however, the multiple correlation coefficient was significantly high (0.622). Standard regression coefficients between Hb and SFR, FEP were significantly high (p<0.01). When Ht and GB were added to these 4 variables, multiple correlation coefficients (male, 0.906; female, 0.957) were remarkably high, which means serum-related variables such as Ht and GB have an undeniably important role as explanatory variables of hemoglobin levels. These standard regression coefficients showed seasonal changes.

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Students in a women's college were investigated for taste acuity for salt, discrimination of salt concentrations in food, and anthro-pometrical (the body mass index, and systolic and diastolic blood pressures) and biochemical nutritional parameters (blood hemoglobin, plasma zinc, plasma copper, plasma vitamin A, plasma retinol-binding protein, urinary sodium, urinary potassium, urinary magnesium, urinary calcium and urinary zinc).
Among 95 students who participated in the test for discrimination of salt concentrations, which was repeated 6 times with 5 different test samples, only 43 (45.3%) committed no mistakes. The detection threshold for taste of salt was significantly associated with neither the discriminability of salt concentrations nor any biochemical parameters.
Levels of plasma zinc (PZn), urinary zinc (UZn) and plasma vitamin A (VA) were lower in the present subjects than in those reported previously. The rate of correct discrimination (RCD) was significantly correlated with PZn and VA positively, and with urinary sodium (UNa) and urinary potassium (UK) negatively. In the factor analysis to in-vestigate the interrelationship of nutritional parameters, 6 factors with significance were extracted, among which factors 3 and 4 were related to RCD. Factor 3 had large loadings on VA, plasma retinol-binding protein (RBP) and RCD, and factor 4 was positively loaded on UNa and UK and negatively on UZn and RCD. In the stepwise multiple regression analysis (RCD being the dependent variable), significant independent variables selected were VA, UK, PZn, systolic blood pressure and UNa. From these results, the college-aged women's failure in discriminating salt concentrations in food was likely to be related to (1) vitamin A inadequacy, (2) mild Zn deficiency and (3) excessive intakes of Na and K.

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The exopeptidase activities of five different strains of bifidobacteria occurring habitually in healthy human intestinal canal were measured on 61 synthetic substrates. The cluster analysis, based on the results, indicates that four strains, with the exception of Bifidobacterium adolescentis a M101-4, have similar exopeptidase profiles. All CFE from these five strains contained at least three kinds of aminopeptidases (aminopeptidase with broad substrate specificity, amino-peptidase hydrolyzing selectively X-Pro type and aminopeptidase hy-drolyzing selectively Pro-X type) and carboxypeptidase.

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Transport and metabolism of L-Carnosine (β-alanyl-L-histidine) were studied in rat small intestine. Carnosine administered orally was found in rat serum as well as small intestine and liver, followed by an increase of histidine. At ten minutes after Carnosine infusion per os, the carnosine content of the hepatic portal vein increased with the dose. On the other hand, the histidine content increased two-fold but did not vary with the dose. These results suggest that part of the carnosine administered orally is hydrolyzed to, β-alanine and histidine in the small intestine.
Carnosinase activity was present in many rat tissues and was most active in kidney in the presence of Mn²⁺ . However, in the absence of Mn²⁺ Carnosinase activity in small intestine was found to be the same level as that of kidney. A study has been made of the distribution of carnosinase along the small intestine of adult rat. The dipeptidase was distributed along the whole length of the small intestine with maximum hydrolytic activity in the jejunum, and was localized in the cytosol of the intestinal mucosa.
Antiserum prepared against carnosinase purified from kidney inhibited the activity of small intestine as well as that of kidney.

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