IGF1 and endometriosis: In addition to that, they cause macrophages to produce neurotrophic factors such as brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and insulin-like growth factor-1 (IGF-1), which cause neurogenesis in the endometriosis lesions, sensitization of the nerve ending, and upregulation of the perception of pain [30].