Ibfelt et al. (2014) found that TNF alpha induces IR through inhibiting the tyrosine phosphorylation of insulin receptor substrates, and also affects the intracellular glucose transport through downregulating the expression of GLUT4. Miao et al. (2012) found that TNF alpha is positively correlated with FoxO1 expression and FoxO1 might increase the production of pro-inflammatory factors in diabetic hepatocytes with IR. Li et al. (2017) found the association of FoxO1 signaling with the aggravation of inflammation and occurrence of IR in PCOS macrophages. Here, TNF is linked to polycystic ovary syndrome.