Influence of estradiol-17 beta and progesterone on catechol-O-methyltransferase and monoamine oxidase activities in uterine artery and myometrium of ovariectomized pigs.

Activities of catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO) were determined in uterine artery and myometrium of uterine horn in ovariectomized pigs. It was considered that in uterine artery COMT activity increased after estradiol (E2) by 91.4% (p < 0.01), after progesterone (P) by 194.3% (p < 0.001) and after simultaneous administration of E2+P by 109.3% (p < 0.01). In myometrium this activity rose after E2 by 56.3% (p < 0.01) and after simultaneous using E2+P rose by 64.3% (p < 0.01) in relation to COMT activity determined in ovariectomized animals (Control). MAO activity in uterine artery decreased by 55.4% after P (p < 0.01) and also after simultaneous administration of E2+P by 58.7% (p < 0.01). In myometrium this activity decreased after E2 by 35.5% (p < 0.05) and after E2+P by 51.2% (p < 0.01), whereas increased after P by 30.6% (p < 0.05) in relation to MAO activity determined in control. Changes of MAO and COMT activities after E or P administration in ovariectomized animals denote that the hormones can participate in regulation of NA concentration in adrenergic synapse by the way of qualitative and quantitative changes of this mediator decomposition rate. E2 causes decrease of NA concentration in adrenergic synapse of uterine artery, whereas P operates the opposite way, as increaser.