Effects of a training program on resting plasma 2-hydroxycatecholestrogen levels in eumenorrheic women.
Catecholestrogens (CE) represent a major metabolic pathway in estrogen metabolism. Previous information on CE and training is limited to two cross-sectional studies that did not involve standardized training. Our purpose, by means of a prospective design, was to evaluate the effects of a brief, exhaustive training program on resting plasma concentrations of 2-hydroxy CE. The experimental design spanned two menstrual cycles; a control cycle and a training cycle. The subjects were nine previously untrained, eumenorrheic women [body fat: 24.8 +/- 1.0 (SE) %]. Data were collected during the follicular (FPh) and the luteal phases (LPh). Posttraining FPh and LPh tests were held the day after the last day of a 5-day period of training on a cycle ergometer. Total 2-hydroxyestrogens (2-OHE) averaged 200 +/- 29 pg/ml during the FPh and 420 +/- 54 pg/ml during the LPh (P < 0.05). Levels of total 2-methoxyestrogens (2-MeOE) were 237 +/- 32 pg/ml during the FPh and 339 +/- 26 pg/ml during the LPh (P < 0.05). After training, although the plasma levels of 2-OHE significantly decreased (21%; P < 0.05) during the LPh, the actual CE formation (as estimated from the 2-OHE-to-total estrogens ratio) increased (+ 29%; P < 0.05). CE activity, as expressed by the 2-MeOE-to-2-OHE ratio, showed significantly higher values in both phases (FPh, + 14%; LPh, + 13%; P < 0.05). At the same time, resting levels of norepinephrine (NE) were increased by 42% (P < 0.05). CE strongly inhibit biological decomposition of NE by catechol-O-methyltransferase (COMT). Results of the present study suggest that, in response to training, CE are increasingly competing with the enzyme COMT, thus preventing premature NE deactivation.
De Crée
C
C
Dept. of Applied and Experimental Reproductive Endocrinology, Institute for Gyneco-Endocrinological Research, Leuven, Belgium.
Ball
P
P
Seidlitz
B
B
Van Kranenburg
G
G
Geurten
P
P
Keizer
H A
HA
D000328:Adult; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D002395:Catecholamines / Q000097:blood; D004967:Estrogens / Q000097:blood; D002393:Estrogens, Catechol / Q000097:blood*; D005260:Female; D006728:Hormones / Q000097:blood; D006801:Humans; D008297:Male; D008597:Menstrual Cycle / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*
D002395:Catecholamines; D004967:Estrogens; D002393:Estrogens, Catechol; D006728:Hormones; D002394:Catechol O-Methyltransferase