Enzymology of human myometrium: Variations related to the hormonal milieu

Abstract

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.

Uterine contractility is strongly influenced by steroids and glucose metabolism: anin vitrostudy on bovine myometrium

“…This hypothesis is strengthened by the fact that in rat uteri, the highest activity of glycolytic enzymes is present during estrus [27,28]. In fact, estradiol increases the expression of hexokinase, phosphofructokinase and other enzymes involved in glycolysis [29,30].…”

Effects of rosiglitazone, a PPAR‐γ agonist, on the contractility of bovine uterus in vitro

“…For smooth muscle contraction to occur, two factors are essential: (i) an increase in intracytoplasmatic calcium ions concentrations ([Ca2+]i) (Sanders, 2001), and (ii) an adequate amount of available energy (Gonzales et al. , 1976; Herrmann et al. , 1987).…”

“…The energetic source is mainly represented by glucose, and glycolysis is important for myometrial contraction (Gonzales et al. , 1976; Herrmann et al. , 1987).…”

“…The energetic source is mainly represented by glucose, and glycolysis is important for myometrial contraction (Gonzales et al, 1976;Herrmann et al, 1987). Thiazolidinediones (TZDs) are drugs currently used in human medicine for the treatment of noninsulin-dependent diabetes mellitus (NIDDM) or type II diabetes (Gurnell et al, 2003;Staels & Fruchart, 2005).…”

Activities in Leiomyomas and Myometrium of Enzymes Involved in Energy Metabolism

“…In a previous study we showed cyclic changes of HAD activity which was highest in secretory phase myometrium, whereas gly colytic enzymes remained stable throughout the menstrual cycle [20]. In leiomyomas the cyclical changes of HAD are still present, and in both phases HAD activity is higher than in the adjacent myometrium.…”