Since obesity is associated with LVH [57] and leptin levels are significantly increased in obesity, many researchers believe that leptin actually contributes to LVH. In vitro studies done on neonatal rat ventricular myocytes exposed to 3.1 nmol/L of leptin for 24 hours significantly increased cell surface area by 42% [14]. The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.