Monoamine oxidase activity in the uterine and mesenteric arteries, vessels of ovarian pedicle and myometrium of pigs during the oestrous cycle.

Activities of total monoamine oxidase (MAO-T) and of both subtypes: MAO-A and MAO-B were examined in the uterine artery, vessels of ovarian pedicle (subovarian veno-arterial network), mesenteric artery and myometrium on the 0-2nd, 13-14th and 16-18th days of the oestrous cycle of pigs. It was found that in the uterine artery MAO-T, MAO-A and MAO-B activities were the highest on the 0-2nd days (100%); on day 13-14 they were lower by 85.4, 84.8 and 87.4% (p < 0.01), respectively, and on days 16-18 they were lower by 52.4, 57.5 and by 54.1% (p < 0.01) in comparison with the value on the 0-2nd days of ovarian cycle. The activities of MAO-T, MAO-A and MAO-B in the vessels of ovarian pedicle on the 0-2nd days were the lowest, whereas on days 13-14 they were the highest (p < 0.01), MAO-T by 445.3%, MAO-A by 315.6%, MAO-B by 344.7%, and they were higher on days 16-18 by 133.8% (p < 0.01), 85.9 (p < 0.05) and by 281.5% (p < 0.01) in comparison with the value on the 0-2nd day of ovarian cycle, respectively. The activities of examined enzymes in mesenteric artery were higher on 0-2nd and 16-18th days, whereas MAO-T and MAO-B they were lower by 39.0% and MAO-A by 22.3% (p < 0.05) on 13-14th days of oestrous cycle. In myometrium the activities of MAO-T, MAO-A and MAO-B on the 0-2nd days (100%) were the lowest, whereas on days 13-14 the activities were the highest (p < 0.01), MAO-T by 326.3%, MAO-A by 363.3% and MAO-B by 364.1%, and on days 16-18 the MAO-T and MAO-B activities were also higher by 99.4% and 150.7% (p < 0.01) respectively, whereas MAO-A activity was similar to the value on the 0-2nd days. The high MAO activity in the vessels of pig ovarian pedicle may be a significant factor in the ovarian vasotone decrease and increase in the ovarian blood flow during the luteal phase of ovarian cycle.