Mean (± SE) serum prolactin according to ascending COMT enzymatic activity level in women with PCOS. COMT relative activity was ordered, based on the two COMT haplotypes of each subject, from 1 (low activity) to 6 (high activity) in accordance with reported information on enzyme activity (Nackley et al., 2006). Ordered COMT haplotypes: 1=ACCG/ACCG, 2=ACCG/ATCA, 3= ACCG/GCGG, 4= ATCA/ATCA, 5=ATCA/GCGG, 6=GCGG/GCGG. Mean prolactin level decreased linearly from low to high activity (P < 0.0002).