Fig. 6

Impairment of insulin signalling using a combined insulin-fructose treatment protocol. Human astrocytes treated with ± 1 μM insulin ± 1 mM fructose for 4d (a). Representative immunoblots showing reductions in IRβ and pAkt with no impact on total IRS1 or downstream signalling through p44/42 MAPK. *α-tubulin was used as a loading control for blots and a representative loading control is shown. Molecular weight markers are indicated (kDa). b Bar charts show quantification of immunoblots, pAkt was normalised to Akt/α-tubulin. c qPCR analysis of IRβ RNA at 4d shows no differences at the RNA level indicating receptor decreases are mediated by receptor degradation. Data are mean + SEM (n = 3, 3 replicates/experiments, One way ANOVA with post-hoc analysis, *p < 0.05, **p < 0.01, ***p < 0.001