FOS and Hypoglycemia: Insulin treatment resulted in pronounced hypoglycemia (blood sugar level in mmol/l: saline, 5.68 ± 0.06; insulin, 2.28 ± 0.19; Student’s t−test; t = 16.74, p < 0.001 (n = 4/group)), which caused a significant decrease in the proportion of Fos and nesfatin−1 double−labeled neurons in the nesfatin−1 cell population (Figure 3C,E left).