IGF2 and obesity due to melanocortin 4 receptor deficiency: Since leptin is involved in the regulation of metabolism and shifts in placental Igf2 have been linked to states of poor nutrition or fetal stress (reviewed in [93,94]), our results suggest, for the first time, that the predisposition for the offspring of smokers to develop obesity and cardiovascular disease later in life is linked to NIC-induced signals that mimic maternal poor nutrition.