title: Mechanisms underlying the beneficial effect of soy protein in improving the metabolic abnormalities in the liver and skeletal muscle of dyslipemic insulin resistant rats.
abstract: OBJECTIVE
  The present study analyzes the effect of the replacement of dietary casein by soy protein on the mechanisms underlying dyslipidemia, liver steatosis and altered glucose and lipid metabolism in the skeletal muscle which developed in rats fed long-term a sucrose-rich diet (SRD).
  
  
  METHODS
  Wistar rats were fed a SRD for 4 months. From months 4 to 8, half the animals continued with the SRD, and the other half were fed a SRD in which the source of protein casein was replaced by soy. The control group received a diet with cornstarch as source of carbohydrate.
  
  
  RESULTS
  Compared to SRD-fed animals, the rats fed soy showed: A--in the liver: reduction of triglyceride and cholesterol storage and decreased steatosis; normalization of mature forms of the protein mass levels of SREBP-1 and the activities of lipogenic enzymes, while the protein mass level of PPAR-α and fatty acid oxidase activity increased. B-in the gastrocnemius muscle: normalization of the enhanced lipid storage and the altered glucose oxidation, improving glucose phosphorylation; decreasing protein mass level of nPKCθ in the membrane fraction; reversion of the impaired insulin-stimulated glucose transporter Glut-4, and glucose-6-phosphate and glycogen concentrations. Besides, dyslipidemia and glucose homeostasis returned to control values.
  
  
  CONCLUSIONS
  This study provides new information concerning some key mechanisms related to the effect of dietary soy on hepatic lipid metabolism and insulin action in the skeletal muscle in the presence of pre-existing dyslipidemia and insulin resistance induced by a SRD.
authors.affiliation: Department of Biochemistry, School of Biochemistry, University of Litoral, Ciudad Universitaria El Pozo cc 242, 3000, Santa Fe, Argentina.
authors.forename: M E
authors.initials: ME
authors.lastname: Oliva
authors.forename: A
authors.initials: A
authors.lastname: Chicco
authors.forename: Y B
authors.initials: YB
authors.lastname: Lombardo
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D019422:Dietary Sucrose / Q000008:administration & dosage / Q000009:adverse effects*; D050171:Dyslipidemias / Q000178:diet therapy*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005234:Fatty Liver / Q000178:diet therapy; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D019298:Glucose-6-Phosphate / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D047493:PPAR alpha / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D030262:Soybean Proteins / Q000008:administration & dosage*; D051780:Sterol Regulatory Element Binding Protein 1 / Q000378:metabolism; D014280:Triglycerides / Q000097:blood; D015430:Weight Gain
chemical_list: D001786:Blood Glucose; D019422:Dietary Sucrose; D005230:Fatty Acids, Nonesterified; D051275:Glucose Transporter Type 4; D007328:Insulin; D047493:PPAR alpha; C495694:Slc2a4 protein, rat; D030262:Soybean Proteins; C497389:Srebf1 protein, rat; D051780:Sterol Regulatory Element Binding Protein 1; D014280:Triglycerides; D019298:Glucose-6-Phosphate; D006003:Glycogen; D002784:Cholesterol