Fig. 4.

Brain uptake of ¹²⁵I-insulin in WT mice at 8, 24, and 52 weeks. A) Experimental scheme. WT mice were bolus injected with 100μCi of ¹²⁵I-insulin into the femoral vein. At the end of the experiment, 100μCi of ¹³¹I-albumin was injected to serve as a marker of V_p. The brain regions were dissected and assayed for radioactivity. B) The PS value estimates for ¹²⁵I-insulin uptake in various brain regions are shown. Data represent mean±SD, n = 3–5. *p<0.05, ***p<0.001, ****p<0.0001; two-way ANOVA with Bonferroni post-tests. C) The overall brain accumulation was assessed as % ID/g. **p<0.01; one-way ANOVA with Bonferroni post-tests.