SIRT1 and obesity due to melanocortin 4 receptor deficiency: Interestingly, only female mice display obesity or diet-induced obesity with POMC neuron-specific disruptions of genes including estrogen receptor α, Esr1, (ERα) [14], transcriptionally active p63, Trp63, (TAp63) [13], steroid receptor coactivator-1, Ncoa1, (SRC-1) [15], Sirtuin 1, Sirt116 or signal transducer and activator of transcription 3, Stat3, (STAT3) [17].