INS and obesity due to melanocortin 4 receptor deficiency: With the aim to better understand the molecular basis of the interplay between obesity and insulin resistance in skeletal muscle in PCOS, we investigated the expression of key components of the insulin signaling pathway, main energy sensor—AMP-activated kinase (AMPK), enzymes involved in lipid mobilization and β-oxidation, as well as markers of oxidative damage and inflammation in the gastrocnemius muscle of an established Wistar rat 5α-dihydrotestosterone (DHT)-induced model of PCOS, additionally challenged by postnatal overfeeding gained through litter size reduction.