PDGFRB and obesity due to melanocortin 4 receptor deficiency: PDGFRβ and GSK3 may regulate body weight, as PDGFRβ and GSK3 deficiencies reduce high-fat diet-induced obesity in mice.45,46 Fidaxomicin is minimally absorbed into the circulation, so it is speculated that its inhibition of intestinal PDGFRβ and GSK3β may regulate body weight indirectly.