A study on different courses of DN in an animal model of STZ-induced DN indicated that iNOS might have different effects in different stages of the disease: in a model of very early stage DN induced by STZ for one week, glomerular hypertrophy and high filtration were associated with the high expression of insulin-like growth factor-1 (IGF-1) in the kidney. The gene discussed is NOS2; the disease is liver dysplastic nodule.