Biomedical subjects

T Noguchi

Publications and source records attributed to T Noguchi.

At least 1,045 records · Page 58Linked to original sources

PubMed1980

Studies on vitamin D metabolism: catabolism of 1 alpha, 25-dihydroxyvitamin D3 and 1 alpha-hydroxyvitamin D3 to a metabolite inactive on bone mineral mobilization.

A heretofore unknown metabolite of vitamin D3 was isolated from the 1 alpha, 24, 25-trihydroxyvitamin D3 fraction of lipid extracts obtained from plasma of rats which were given intravenous or oral doses of 100 pmol/100 g of either 1 alpha-hydroxyvitamin D3 or 1 alpha, 23-dihydroxyvitamin D3. Doses of 25-250 pmoles of the new metabolite when given to a vitamin D deficient rat were completely inactive in terms of stimulating the classic vitamin D response of bone calcium mobilization. The nature of the metabolism of 1 alpha-hydroxyvitamin D3 or 1 alpha, 25-dihydroxyvitamin D3 to the metabolite is not clear at the present time, but it is probable that neither of these steroids undergo side-chain cleavage to yield the new metabolite.

Animals↗

PubMed1980

Effect of acute nitrogen dioxide exposure on the composition of fatty acids in lung and liver phospholipids.

In order to examine the effects of NO2 on the fatty acid content of the lung and liver phospholipids, the phospholipid fractions of rats exposed to 20 ppm NO2 for 20 and 40 h were extracted and analyzed using gas chromatography. Among the ftty acid species in the lung, the relative amount of palmitic acid, palmitoleic acid and linoleic acid increased significantly, whereas myristic acid, stearic acid and oleic acid decresed significantly after exposure to NO2. These changes in the composition of fatty acids are discussed in comparison with the results of acute, subacute and chronic exposure to NO2 reported by other workers. In the case of the fatty acid species in the liver, a significant increase for stearic acid and arachidonic acid and a decrease in oleic acid were observed.

Animals↗

PubMed1980

Phosphopeptides and soluble calcium in the small intestine of rats given a casein diet.

1. Semi-synthetic diets containing 200 g protein/kg were meal-fed for 1.5 h to groups of rats. The contents of the whole small intestinal tract were collected and the amount of soluble calcium was determined. 2. In the rats given 200 g casein/kg diet, formation of a fraction containing macrophosphopeptide in the small intestine was confirmed by gelfitration of the intestinal contents on Sephadex G-25. However, this macrophosphopeptide fraction was not found when casein alone was fed. 3. In the intestinal contents at 2.5 h after ingestion, the amounts of both soluble Ca and phosphorus were significantly higher in rats fed the casein diet than in those fed diets containing egg albumin, isolated soya-bean protein or an amino acid mixture. However, the amount of insoluble Ca was least in rats fed the casein diet.

Animals↗

PubMed1980

Regulation of rat-liver tyrosine-aminotransferase mRNA by hydrocortisone and by N6,O2'-dibutyryladenosine 3',5'-phosphate.

The intraperitoneal injection of either hydrocortisone of N6,O2'-dibutyryladenosine 3',5'-phosphate (Bt2cAMP) results in a specific increase in functional tyrosine aminotransferase mRNA (mRNATAT) activity in rat liver that is proportional to the degree of enzyme induction. Both require continuous RNA synthesis. There are several differences in the response to these inducers: (a) the magnitude of the increase is greater following hydrocortisone injection than after Bt2cAMP; (b) the peak response is seen within 1 h following the injection of Bt2cAMP as compared to the 5 h required for the maximal response following hydrocortisone injection; (c) finally, although both responses are rapid, the lag period which precedes the accumulation of functional tyrosine aminotransferase mRNA activity following the injection of hydrocortisone is at least 20 min whereas following Bt2cAMP it is 5-10 min. The administration of actinomycin D to rats 5 h after they were treated with hydrocortisone causes an additional twofold increase in tyrosine aminotransferase enzymatic activity, a phenomenon known as superinduction, but does not prevent the normal decrease in its mRNA seen at this time. This dissociation of enzyme and mRNA activities indicates that superinduction of tyrosine aminotransferase is not due to a selective stabilization of the mRNA which codes for this protein.

Animals↗

PubMed1980