In hyperglycaemic models of insulin resistance/type 2 diabetes, impaired erectile function was accompanied by a slight [18] or nule [20] impairment of the neural NO-mediated relaxant responses, which has led to the suggestion that functionally altered nNOS-mediated signalling does not have much pathophysiologic relevance to the development of ED in these hyperglycaemic models of type 2 diabetes. Here, NOS1 is linked to type 2 diabetes mellitus.