The goal of the present study was to investigate changes on
glucose homoeostasis and of the
insulin receptor (IR) and
insulin receptor substrate-1 (IRS-1) signalling in pancreatic islets from
MSG-obese mice submitted to or not submitted to swim training. Swim training of 90-day-old
MSG mice was used to evaluate whether signalling pathways of the IR and IRS-1 in islets are involved with the
insulin resistance and
glucose intolerance observed in this obese animal model. The results showed that IR
tyrosine phosphorylation (pIR) was reduced by 42 % in
MSG-obese mice (
MSG, 6.7 ± 0.2 arbitrary units (a.u.); control, 11.5 ± 0.4 a.u.); on the other hand, exercise training increased pIR by 76 % in
MSG mice without affecting control mice (
MSG, 11.8 ± 0.3; control, 12.8 ± 0.2 a.u.). Although the treatment with
MSG increased IRS-1
tyrosine phosphorylation (pIRS-1) by 96 % (
MSG, 17.02 ± 0.6; control, 8.7 ± 0.2 a.u.), exercise training also increased it in both groups (control, 13.6 ± 0.1;
MSG, 22.2 ± 1.1 a.u.). Current research shows that the practice of swim training increases the
tyrosine phosphorylation of IRS-1 which can modulate the effect caused by
obesity in
insulin receptors.