Effect of chronic experimental stress on insulin sensitivity in susceptible mice to diabetes / 中华老年医学杂志

ABSTRACT

Objective This study was to compare the effects of chronic experimental stress and aging on insulin sensitivity at insulin receptor of liver plasma membranes and its autophosphorylation in the aged mice compared with those in the young and the adult diabetes-susceptible mice. Methods Diabetes-susceptible mice was induced by streptozotocin in 40 1.5-month-old mice (young mice), 40 15-month-old mice (adult mice) and 40 20-month-old mice (aged mice). These mice were randomly divided into the stress groups and control groups, respectively. Each group contained 20 mice. Stress groups were exposed to multiple stressors (restrain, rotation, crowding) for 6 weeks. The levels of fasting blood glucose (FBG) and fasting plasma insulin (FIns) were measured. The index of insulin sensitivity (ISI) was calculated. The numbers (R_~1 , R_~2 , R) and affinity (K_~1 , K_~2 , K) of insulin receptors on liver plasma membranes were investigated by using Scatchard analysis. The numbers of insulin-stimulated (10~-7 mol/L) phosphorylated insulin receptor (PINSR) on liver plasma membranes was assayed by ELISA. Results After 6-week stress, FBG levels were significantly higher with aging 〔young mice (10.3?6.2)mol/L, adult mice (15.2?3.6)mol/L, aged mice (18.9?2.9)mol/L, P