title: Taurine-induced insulin signalling improvement of obese malnourished mice is associated with redox balance and protein phosphatases activity modulation.
abstract: OBJECTIVE
  Obese protein malnourished mice display liver insulin resistance and taurine (TAU) seems to attenuate this effect. The association between early-life malnutrition and hepatic redox balance in diet-induced insulin resistance is unknown. We investigated TAU supplementation effects upon liver redox state and insulin signalling in obese protein malnourished mice.
  
  
  METHODS
  Weaned male C57BL-6 mice were fed a control (14% protein - C) or a protein-restricted diet (6% protein - R) for 6 weeks. Afterwards, mice received a high-fat diet (34% fat - HFD) for 8 weeks (CH - RH). Half of the HFD-mice were supplemented with TAU (5%) throughout the treatment (CHT - RHT). Body and tissues' weight, respiratory quotient (RQ), glucose tolerance and insulin sensitivity, hepatic oxidant and antioxidant markers and insulin cascade proteins were assessed.
  
  
  RESULTS
  Protein restriction leads to typical features whereas HFD was able to induce a catch-up growth in RH. HFD-groups showed higher energy intake and adiposity, lower energy expenditure and altered RQ. Glucose tolerance and insulin sensitivity were impaired in HFD-groups and TAU attenuated these effects. H2 O2 content was increased in CHT and RHT despite no differences in antioxidant enzymes and GSH concentration. AKT and PTEN phosphorylation were significantly increased in CHT but not in RHT.
  
  
  CONCLUSIONS
  Our data provide evidence for an association between TAU-induced improved glycaemic control because of PTEN inactivation and higher AKT phosphorylation. These effects seem to be related with altered hepatic redox balance in obese mice, and this effect is impaired by protein malnutrition.
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Cappelli
authors.forename: Claudio C
authors.initials: CC
authors.lastname: Zoppi
authors.forename: Helena C
authors.initials: HC
authors.lastname: Barbosa-Sampaio
authors.forename: José M
authors.initials: JM
authors.lastname: Costa
authors.forename: André O
authors.initials: AO
authors.lastname: Protzek
authors.forename: Priscila N
authors.initials: PN
authors.lastname: Morato
authors.forename: Antonio C
authors.initials: AC
authors.lastname: Boschero
authors.forename: Everardo M
authors.initials: EM
authors.lastname: Carneiro
mesh_terms: D000818:Animals; D001823:Body Composition; D059305:Diet, High-Fat / Q000009:adverse effects*; D019587:Dietary Supplements; D005947:Glucose / Q000378:metabolism; D006128:Growth; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D008099:Liver / Q000378:metabolism*; D008297:Male; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000178:diet therapy / Q000209:etiology / Q000378:metabolism*; D010084:Oxidation-Reduction; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D011488:Protein Deficiency / Q000150:complications; D013654:Taurine / Q000627:therapeutic use*
chemical_list: D007328:Insulin; D013654:Taurine; D010749:Phosphoprotein Phosphatases; D005947:Glucose
keywords: PTEN; PTP1B; antioxidant enzymes; hydrogen peroxide; liver