title: The α' subunit of β-conglycinin and the A1-5 subunits of glycinin are not essential for many hypolipidemic actions of dietary soy proteins in rats.
abstract: OBJECTIVE
  This study examined the effects of dietary soy protein (SP) lacking different storage protein subunits and isoflavones (ISF) on the abdominal fat, blood lipids, thyroid hormones, and enzymatic activities in rats.
  
  
  METHODS
  Weanling Sprague-Dawley rats (8 males and 8 females/group) were fed diets containing either 20 % casein without or with supplemental isoflavones or alcohol-washed SP isolate or SP concentrates (SPC) prepared from 6 different soy bean lines for 8 weeks.
  
  
  RESULTS
  Feeding of diets containing SPC regardless of their subunit compositions significantly lowered relative liver weights, blood total, free, and LDL cholesterol in both genders (P < 0.05) and also reduced serum free fatty acids (FFA) and abdominal fat in females (P < 0.05) compared to the casein or casein + ISF diets. Dietary SPC significantly elevated the plasma free triiodothyronine (T3) in both genders and total T3 in females compared to the casein diet (P < 0.05). The SPC lacking β-conglycinin α' and either the glycinin A1-3 or A1-5 subunits increased total T3 in males and reduced plasma enzymatic activities of creatine kinase and lactate dehydrogenase compared to casein or casein + ISF diet (P < 0.05).
  
  
  CONCLUSIONS
  Soy isoflavones were mainly responsible for the hypocholesterolemic effects and increased plasma free T3, whereas reduction in FFA, abdominal fat, liver weight and increased plasma total T3 were the effects of the soy proteins. Neither the α' subunit of β-conglycinin nor the A1-5 subunits of glycinin are essential for the hypolipidemic properties of soy proteins.
authors.affiliation: Nutrition Research Division, Food Directorate, Health Products and Food Branch, Health Canada, Banting Research Centre, Ottawa, ON, K1A 0K9, Canada.
authors.forename: Qixuan
authors.initials: Q
authors.lastname: Chen
authors.forename: Carla
authors.initials: C
authors.lastname: Wood
authors.forename: Christine
authors.initials: C
authors.lastname: Gagnon
authors.forename: Elroy R
authors.initials: ER
authors.lastname: Cober
authors.forename: Judith A
authors.initials: JA
authors.lastname: Frégeau-Reid
authors.forename: Stephen
authors.initials: S
authors.lastname: Gleddie
authors.forename: Chao Wu
authors.initials: CW
authors.lastname: Xiao
mesh_terms: D050153:Abdominal Fat / Q000502:physiology; D000818:Animals; D000924:Anticholesteremic Agents / Q000737:chemistry*; D052179:Antigens, Plant / Q000737:chemistry*; D001835:Body Weight; D002364:Caseins / Q000008:administration & dosage; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D005260:Female; D005916:Globulins / Q000737:chemistry*; D007529:Isoflavones / Q000008:administration & dosage; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D055314:Seed Storage Proteins / Q000737:chemistry*; D030262:Soybean Proteins / Q000737:chemistry*; D013025:Glycine max / Q000737:chemistry; D014280:Triglycerides / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D000924:Anticholesteremic Agents; D052179:Antigens, Plant; D002364:Caseins; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D005916:Globulins; D007529:Isoflavones; D055314:Seed Storage Proteins; D030262:Soybean Proteins; D014280:Triglycerides; C013894:beta-conglycinin protein, Glycine max; D014284:Triiodothyronine; C011474:glycinin