INS and polycystic ovary syndrome: First, in young women with PCOS, there was a severe attenuation of insulin stimulation of the p42/p44 MAP kinase pathway in muscle compared to controls (with p42/p44 MAP kinase activity actually reducing in response to insulin) although the group was too small to detect any correlation between BMI and the defective regulation of p42/p44 MAP kinase in the PCOS group [2].