Responses of Catecholestrogen Metabolism to Acute Graded Exercise in Normal Menstruating Women before and after Training

Abstract

It has been hypothesized that exercise-related hypo-estrogenemia occurs as a consequence of increased competition of catecholestrogens (CE) for catechol-O-methyltransferase (COMT). This may result in higher norepinephrine (NE) concentrations, which could interfere with normal gonadotropin pulsatility. The present study investigates the effects of training on CE responses to acute exercise stress. Nine untrained eumenorrheic women (mean percentage of body fat +/-SD: 24.8 +/- 3.1%) volunteered for an intensive 5-day training program. Resting, submaximal, and maximal (tmax) exercise plasma CE, estrogen, and catecholamine responses were determined pre- and post training in both the follicular (FPh) and luteal phase (LPh). Acute exercise stress increased total primary estrogens (E) but had little effect on total 2-hydroxyestrogens (2-OHE) and 2-hydroxyestrogen-monomethylethers (2-MeOE) (= O-methylated CE after competition for catechol-O-methyltransferase). This pattern was not significantly changed by training. However, posttraining LPh mean (+/-SE) plasma E, 2-OHE, and 2-MeOE concentrations were significantly lower (P < 0.05) at each exercise intensity (for 2-OHE: 332 +/- 47 vs. 422 +/- 57 pg/mL at tmax; for 2-MeOE: 317 +/- 26 vs. 354 +/- 34 pg/mL at tmax). Training produced opposite effects on 2-OHE:E ratios (an estimation of CE formation) during acute exercise in the FPh (reduction) and LPh (increase). The 2-MeOE:2-OHE ratio (an estimation of CE activity) showed significantly higher values at tmax in both menstrual phases after training (FPh: +11%; LPh: +23%; P < 0.05). After training, NE values were significantly higher (P < 0.05). The major findings of this study were that: training lowers absolute concentrations of plasma estrogens and CE; the acute exercise challenge altered plasma estrogens but had little effect on CE; estimation of the formation and activity of CE suggests that formation and O-methylation of CE proportionately increases. These findings may be of importance for NE-mediated effects on gonadotropin release.

A influência do ciclo menstrual na flexibilidade em praticantes de ginástica de academia

“…However, other studies (4,13,14) show that variations in the estrogen and progesterone levels during the MC, affect the feminine physiology in many factors such as: use of energetic substrate in different training intensities and volumes, oxygen consumption, energetic substrate storage and fats oxidation. Yet, these physiological changes did not demonstrate significant alterations in the flexibility levels in the three phases of the MC of the actual study.…”

Exercise Effect on Oxidative Stress Is Independent of Change in Estrogen Metabolism

“…However, it has been hypothesized that exercise may alter estrogen metabolism in a manner that could alter cancer etiology (17). We are aware of several prior studies that have examined the effects of exercise training on estrogen metabolism among premenopausal women (18)(19)(20)(21) and one in postmenopausal women (17). Of these, only one (22) has observed an intervention effect on the 2:16 ratio in a subset of participants.…”

“…Ours is the first to examine the effect on the 2:4 ratio. Three publications reported on the observed effects of 5 days of intensive aerobic exercise training on estrogen metabolites (19)(20)(21). None of these studies noted significant changes in metabolites during the follicular phase, but significant decreases were noted for 2-hydroxyestrogens after 5 days of intensive training during the luteal phase (20).…”

Physical activity as a negative modulator of estrogen-induced breast cancer

“…Similarly, in two studies, in which an aerobic exercise intervention was conducted over 12 weeks for eumenorrheic pre-menopausal women [84] in one study and over 12 months for the post-menopausal women in the other study [85], the urinary excretion of 2-OHE 1 and 16a-OHE 1 or their ratio was not significantly altered. However, two other studies [86,87] showed that exercise training promoted the formation of 2-MeOE 2 and 4-MeOE 2 , which may favorably alter breast epithelial cell proliferation [29]. These studies investigated the effect of exercise training over two consecutive menstrual cycles, and reported that the 2-MeOE 2 / 2-OHE 2 and 4-MeOE 2 /4-OHE 2 level ratios were higher post-training, indicating the possible protective effects of sports participation against breast cancer [86,87].…”

“…However, two other studies [86,87] showed that exercise training promoted the formation of 2-MeOE 2 and 4-MeOE 2 , which may favorably alter breast epithelial cell proliferation [29]. These studies investigated the effect of exercise training over two consecutive menstrual cycles, and reported that the 2-MeOE 2 / 2-OHE 2 and 4-MeOE 2 /4-OHE 2 level ratios were higher post-training, indicating the possible protective effects of sports participation against breast cancer [86,87]. Thus, epidemiological studies that have been performed to date, including the exercise interventional studies, provide some support for exercise producing favorable changes in a woman's pattern of estrogen metabolism related to breast cancer risk.…”