PTPN1 and Schnyder corneal dystrophy: Because leptin and insulin are hormones that reduce food intake11, TNF-α, IL-6, and PTP1B are factors known to cause leptin and insulin resistance, and CRP is a protein that inhibits leptin effects, we also measured protein and gene expression for lep, Ins, Tnf, Il6, Ptpn1, and Crp in the omental fat and SCF of SCD-rats and HFD-rats.