title: Long-term high animal protein diet reduces body weight gain and insulin secretion in diet-induced obese rats.
abstract: BACKGROUND
  The effects of a high protein diet on insulin secretion and glucose metabolism have been quite controversial. The aim of this study was to evaluate the effects of long-term isocaloric high animal protein intake on insulin secretion in diet-induced obese rats.
  
  
  RESULTS
  After the experimental period (24 weeks), the high-fat diet-induced obese rats that were fed isocaloric high-protein diets (HP) had lower body weight gain (P < 0.01) and lower visceral fat (P < 0.05) than normal protein (NP) rats. Fasting plasma glucagon-like peptide-1 (GLP-1) was also reduced significantly (P < 0.05), as well as serum insulin levels at 5 min and 10 min by intravenous insulin releasing test. In addition, insulin mRNA and pancreatic duodenal homeodomain-1 (PDX-1), GLP-1 protein expression were both markedly lower in HP rats (P < 0.05), while PDX-1 mRNA in HP rats had no difference from NP rats.
  
  
  CONCLUSIONS
  These results suggest that long-term isocaloric high animal protein intake reduces the acute insulin response in obese rats and the decrease of insulin is associated with both reduced weight gain and inhibition of PDX-1 expression. GLP-1 might be a negative feedback for the balance of energy metabolism secondary to changes of body weight and visceral fat.
authors.affiliation: Department of Endocrinology, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Chen
authors.forename: Yiling
authors.initials: Y
authors.lastname: Wang
authors.forename: Lichuan
authors.initials: L
authors.lastname: Ma
authors.forename: Jiajun
authors.initials: J
authors.lastname: Zhao
authors.forename: Yinyin
authors.initials: Y
authors.lastname: Li
authors.forename: Minglong
authors.initials: M
authors.lastname: Li
mesh_terms: D000818:Animals; D059305:Diet, High-Fat / Q000009:adverse effects*; D004044:Dietary Proteins / Q000494:pharmacology*; D004734:Energy Metabolism / Q000187:drug effects*; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007328:Insulin / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D000078790:Insulin Secretion; D050152:Intra-Abdominal Fat / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009765:Obesity / Q000097:blood / Q000178:diet therapy* / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D015430:Weight Gain / Q000187:drug effects*
chemical_list: D004044:Dietary Proteins; D018398:Homeodomain Proteins; D007328:Insulin; D012333:RNA, Messenger; D015534:Trans-Activators; C084010:pancreatic and duodenal homeobox 1 protein; D052216:Glucagon-Like Peptide 1