Figure 1. Ratio of insulin receptor substrate (IRS)-1^{Ser 307} in Müller cells. A phosphorylation of IRS-1^Ser307 is significantly increased in Müller cells following treatment with tumor necrosis factor–α, but treatment with beta-2-adrenergic receptor agonist, salmeterol significantly decreases phosphorylation levels. Significance was determined by one-tailed, nonparametric Mann–Whitney test on western blot data (*p<0.05 versus high glucose, n=4, #p<0.05 versus normal glucose, n=4).