Enzymology of human myometrium: Variations related to the hormonal milieu

The activities of various enzymes involved in glycolysis, tricarboxylic acid cycle and fatty acid oxidation were assayed in human myometrium. A gradient of the activities from fundal to cervical myometrium was observed. In contrast to studies performed in rodents, cyclic changes of glycolytic enzymes could not be detected. Hydroxyacyl-CoA-dehydrogenase (HAD) activity was higher in secretory phase myometrium and in cases with cystic hyperplasia of the endometrium than in proliferative phase myometrium. In pregnant myometrium, lactate dehydrogenase (LDH) and glycogen phosphorylase (GLP) were increased and in postmenopausal myometrium the activities of phosphofructokinase (PFK), LDH and succinate dehydrogenase (SDH) were decreased as compared to proliferative phase myometrium. We conclude that in the human myometrium, except for HAD, activities of enzymes involved in fuel metabolism are stable throughout the menstrual cycle and that only prolonged hormonal stimulation leads to alterations of some enzyme activities.