Linear correlations of homeostasis model assessment of insulin resistance (HOMA-IR), Δ glycemia ([glycemia after 120 min of insulin bolus] – [glycemia before insulin bolus]) after intracerebroventricular insulin infusion (ICVII) and area under the curve (AUC) after intraperitoneal insulin tolerance test (IPITT) with serum levels of leptin, interleukin (IL)-2 and IL-4. The gene discussed is LEP; the disease is Insulin resistance.