Fig. 8.

Effect of vitamin D₃ injections on plasma and brain IGF-I levels. Plasma and brain tissue derived from control and vitamin D-treated female rats 5 d after stroke were analyzed for IGF-I expression. A, Vitamin D treatments significantly increased circulating IGF-I levels (39.5%) as compared with levels in control rats injected with vehicle alone (*, P < 0.05). Bars represent mean ± sem. B, IGF-I levels were elevated in the ischemic cortex and striatum, but this was only seen in the controls and not the vitamin D₃-treated animals. Thus, IGF-I levels were significantly lower in the ischemic cortex (11.5-fold) and striatum (3.4-fold) of hormone-treated animals. Data were analyzed by two-way ANOVA for hormone treatment and ischemia for each brain region; a, Main effect of hormone treatment; b, main effect of ischemia; c, interaction effect of hormone and ischemia. Group differences were considered significant at P < 0.05. Bars represent mean ± sem; n = 4–5 in each group.