Responsiveness of Plasma 2- and 4-Hydroxycatecholestrogens to Training and to Graduated Submaximal and Maximal Exercise in an Untrained Woman

A single-subject experimental design was used to obtain some preliminary findings on the plasma responses of catechol-estrogens (CE) to acute exercise and brief, but exhaustive training on a cycle ergometer. One previously untrained eumenorrheic female (body fat: 26 % VO₂max: 43.3 ml · kg^-1 · min^-1) participated in this study. Resting CE levels were for „total” (unconjugated + conjugated) 2-hydroxyestrogens (2-OHE) 162 pg/ ml and 350 pg/ml in the follicular (FPh) and luteal phase (LPh), respectively. Plasma total 4-hydroxyestrogen (4-OHE) levels were 41 pg/ml in the FPh and 66 pg/ml in the LPh. For "total" 2-methoxyestrogens (2-MeOE), we found 257 pg/ml in the FPh and 374 pg/ml in the LPh. Resting levels of 2-hydroxy CE following a period of brief, intensive training were decreased during the LPh (2-OHE: - 38 %; 2-MeOE: - 19 %), whereas 4-hydroxy CE were unaffected. After training, the formation of CE as expressed by the 2-OHE:E and 4-OHE:E ratios, was increased by 75 % and 200 % at rest, respectively. CE activity or O-methylation, as estimated from the 2-MeOE:2-OHE ratio, was higher following training (FPh:+ 22 %; LPh:+ 30 %). During acute exercise before training, we observed a small rise proportional to the exercise intensity in the plasma "total" primary estrogen concentrations (FPh: + 28 %; LPh: + 16 %), and no changes in either 2-OHE or 2 MeOE levels. Plasma concentrations of 4-OHE, however, doubled during maximal exercise intensity. The 2-OHE:E and 2-MeOE:2-OHE ratios did not alter during incremental exercise. Training effects on acute exercise responses were only noticed for 4-OHE, which contrary to pre-training conditions, now progessively decreased. The major findings of this study are that in response to training: a) during rest, a greater proportion of CE are formed from a lower amout of precursor hormone, b) the rate of O-methylation of CE increases.

Key words

Catecholamines - catecholestrogens - COMT - estrogens - menstrual cycle - women