SF1 and obesity due to melanocortin 4 receptor deficiency: Conditional deletion of SIRT1 in mice in steroidogenic factor 1 (SF1)-expressing neurons (loxP-flanked exon 4 of Sirt1 with Cre recombinase driven by the Sf1 promoter of the ventromedial hypothalamic nucleus (VMH) resulted in heightened susceptibility to diet-induced obesity, and conversely mice overexpressing SIRT1 in these neurons are more resistant to diet-induced obesity and insulin resistance (Ramadori et al., 2011).