Background: The kinin B1 receptor (B1R), an inducible effector of Kallikrein-Kinin System during inflammation, has been blamed also to influence glucose metabolism and leptin sensitivity.
Aim: To investigate the effects of cafeteria diet (CAF) on hepatic glucose metabolism in B1R knockout mice (B1RKO).
Methods: Two months old male C57Bl/6 wild type and B1RKO mice were fed with standard chow (SC) or CAF ad libitumfor 14 weeks (WT-SC n=7; B1RKO-SC n=8; WT-CAF n=7; B1RKO-CAF n =10). We performed glucose tolerance test (GTT) and insulin tolerance test (ITT) at the last week before organs collection. HOMA IR index was calculated. Quantitative PCR was used to determine hepatic expression of glucose-6-phospatase (G6Pase), glucokinase (GK), phosphoenolpyruvate carboxykinase (PEPCK), fructose 1,6-bisphosphatase (FBPase1) and hepatocyte nuclear factor 4 alpha (HNF4A). We also performed western blot to analyze AKT phosphorylation in liver. Two-way ANOVA was used to analyze differences between groups. Values were expressed as mean ± SEM and p ≤0.05 was considered statistically significant.
Results: Although the increment of glucose area under the curve during GTT was lower in B1RKO-CAF than WT-CAF (WT-SC 46.246 ± 4.302 vs. B1RKO-SC 35.699 ± 3.383; p=0.03; and B1RKO-CAF 28.521 ± 5.338 vs. WT-CAF 56.564 ± 3.477; AUC p=0.0001), B1RKO mice presented a similar decay in glucose levels during ITT as well as HOMA-IR values . While there was a decrease in liver mRNA expression of G6Pase and PEPCK, GK expression increased in mice fed with CAF diet, without differences between genotypes. FBPase1 and HNF4A mRNA expression were not different between groups. Liver AKT phosphorylation increased with CAF in both C57Bl/6 wild type and B1RKO mice.
Conclusion: The increased glucose uptake of B1RKO mice during GTT might not be related to insulin signaling in the liver, since no changes were observed in insulin resistance or in the hepatic expression of gluconeogenesis regulatory enzymes.
P. Espíndola Correia: None. C.B. Gomes: None. P.N. Merello: None. G.R. Natividade: None. C.C. Barros: None. F. Gerchman: None.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (16-0397)