Biomedical subjects

Nobuhiko Tachibana

Publications and source records attributed to Nobuhiko Tachibana.

5 recordsLinked to original sources

PubMed2005

Intake of soy protein isolate alters hepatic gene expression in rats.

Soy protein isolate (SPI) can elicit various physiological effects such as cholesterol lowering and antiobesity effects. To examine whether hepatic gene expression is altered by SPI intake, rats were fed an SPI or casein diet for 8 weeks. After 8 weeks of feeding, liver weight and plasma triglyceride and cholesterol levels were significantly lower in the SPI group than in the casein group. Hepatic gene expression was investigated using DNA microarrays. The expression profiles and statistical analysis showed clear and significant differences between the SPI and casein groups (p < 0.05); in the SPI group, 63 genes were up-regulated and 57 genes were down-regulated, most involved in various physiological functions such as lipid metabolism, antioxidant activity, transcriptional regulation, and energy metabolism. Especially in lipid metabolism, the down-regulated genes are related to fatty acid synthesis and the up-regulated genes are related to cholesterol synthesis and steroid catabolism. These results suggest that SPI intake could maintain homeostasis primarily by modulating lipid and energy metabolism.

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PubMed2004

Soy protein functionality and nutrigenomic analysis.

Soy protein has various biological functions, such as cholesterol-lowering effect, anti-obese, in addition to that nutritive value, and may relieve some lifestyle-related diseases, cancer, osteoporosis, menopausal disorder and so on. Because of the cholesterol-lowering effect of soy protein had been studied extremely and internationally for mechanism and clinical proof, the Ministry of Health and Welfare in Japan had approved soy protein product as a food for special health use (FOSHU) in 1994, and also the FDA in the United States also approved the food labeling for that in 1999. Although, some reports suggested that soy protein changes in expression of the genes concerned with lipid metabolism in liver and in adipose tissue, there are few reports that it is concerned with the comprehensive influence of the intake of soy protein on gene expression. The gene expression of liver in soy protein fed animal has been analyzed with the Affymetrix DNA-microarray. About 33% of 8000 genes in soy fed animals differed compared with those of casein fed. After cluster analysis, significant differences were observed in the gene cluster concerned with lipid metabolism, also in the gene related to energy metabolism, transcription factor, and anti-oxidization enzymes.

Animals↗

PubMed2004

Effects of soybean beta-conglycinin on hepatic lipid metabolism and fecal lipid excretion in normal adult rats.

beta-Conglycinin decreased blood triacylglycerol (TAG) levels in male Wistar adult rats. Liver mitochondrial carnitine palmitoyltransferase activity in the beta-conglycinin-fed group significantly increased as against the casein-fed group. Hepatic fatty acid synthase activity in the beta-conglycinin group significantly decreased as against that of the casein-fed group. Fecal fatty acid excretion in the beta-conglycinin group was significantly higher than in the casein group.

Animals↗

PubMed2002

Isoflavone-free soy protein prepared by column chromatography reduces plasma cholesterol in rats.

To know whether isoflavones are responsible for the hypocholesterolemic effect of soy protein, the effect on plasma cholesterol of isoflavone-free soy protein prepared by column chromatography was examined in rats. Five-week-old male Sprague-Dawley rats were fed cholesterol-enriched AIN-93G diets containing either 20% casein (CAS), 20% soy protein isolate (SPI), 20% isoflavone-free SPI (IF-SPI), 19.7% IF-SPI + 0.3% isoflavone-rich fraction (isoflavone concentrate, IC), or 20% CAS + 0.3% IC for 2 weeks. Plasma total cholesterol concentrations of rats fed SPI and IF-SPI were comparable and were significantly lower than that of rats fed CAS. The addition of IC to the CAS and IF-SPI did not influence plasma cholesterol level. Fecal steroid excretion of the three SPI groups was higher than that of the two CAS groups, whereas the addition of IC showed no effect. Thus, a significant fraction of the cholesterol-lowering effect of SPI in rats can be attributed to the protein content, but the isoflavones and other minor constituents may also play a role.

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PubMedDate not supplied

Ethanol washing does not attenuate the hypocholesterolemic potential of soy protein.

OBJECTIVE: A feeding study in rats investigated the principal active component for the hypocholesterolemic effect of soy protein isolate (SPI) by comparing the effect before and after ethanol washing. METHODS: Five-week-old male Sprague-Dawley rats were fed cholesterol-enriched AIN-93G diets containing 20% casein (CAS), 20% SPI, 20% ethanol-washed SPI (EWS), 18.4% EWS plus 1.6% ethanol extract (EE), or 20% CAS plus 1.6% EE for 2 wk. RESULTS: Plasma cholesterol concentrations in rats fed EWS and SPI were comparable and were significantly lower than those in rats fed CAS. The addition of EE to EWS and CAS did not influence plasma cholesterol level. Fecal steroid excretion of the three SPI groups was higher than that of the two CAS groups. The addition of EE to EWS and CAS showed a tendency to increase acidic steroid and decrease neutral steroid. CONCLUSIONS: In this experiment which used identifiable protein preparations, a significant fraction of the cholesterol-lowering effect of SPI in rats was attributed to its protein component but not to the ethanol-extractable minor constituents including isoflavones.

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