FOS and Hypoglycemia: Overnight fasting did not elevate c-fos mRNA levels in the whole hypothalamus compared to that of fed controls, while acute insulin-induced hypoglycemia significantly induced c-fos mRNA levels [F (2, 8) = 9.14, p = 0.009; Bonferroni’s post hoc test, t(8) = 4.27, p < 0.001] as measured by qPCR (Fig. 1F).