[Changes of nitric oxide and endothelin plasma levels and effects of hormone replacement therapy in postmenopausal women].
OBJECTIVE
To investigate the changes of plasma levels of nitric oxide(NO) and endothelin (ET) when the estrogen level dropped and to assess the effects of hormone replacement therapy (HRT) on NO, ET plasma levels in postmenopausal women.


METHODS
Twenty-six women with regular menses (regular mense group), twenty-eight perimenopausal women with climacteric symptoms (perimenopausal group), seventy healthy postmenopausal women (postmenopausal group) were in duded in this study. Thirty postmenopausal volunteers received oral conjugated estrogen/medroxyprogesterone acetate (post menopause group I) and twenty others took only calcium (post menopause group II) for 6 months. Plasma NO, ET, follicle-stimulation hormone (FSH) and estradiol (E2) levels were measured for all the women.


RESULTS
The levels of NO were significantly lower in perimenopausal group (23.8 +/- 15.1) mumol/L and postmenopausal group (20.0 +/- 12.1) mumol/L than those of regular mense group (33.2 +/- 15.5) mumol/L (P < 0.05, P < 0.01). The mean concentrations of ET were significantly higher in both of perimenopausal (59.3 +/- 14.2) pg/L and postmenopausal groups (65.3 +/- 16.2) pg/L than those of regular mense group (51.1 +/- 15.6) pg/L (P < 0.01). Plasma NO (32.9 +/- 16.1) mumol/L and E2(47.5 +/- 12.9) pg/L values were significantly higher, and ET (52.2 +/- 12.0) pg/L values significantly lower than baselines of NO (20.3 +/- 11.1) mumol/L, E2(7.9 +/- 4.8) ng/Land ET(62.6 +/- 18.9) pg/L, respectively, in menopause group I after treatment for 6 months (P < 0.01). There was no difference in NO, ET and E2 concentrations in menopause group II before and after taking calcium for 6 month (P > 0.05). E2 had a significant positive correlation with NO and significant negative correlation with ET and FSH.


CONCLUSIONS
HRT results in an increased level of NO and decreased level of ET in postmenopausal women. This may be one of the mechanisms by which HRT provides cardiovascular benefit.
Lai
A
A
Department of Obstetrics and Gynecology, Beijing Fuxing Hospital, Affiliated Capital University of Medical Science 100038, China.
Zhang
J
J
Ding
L
L
D000328:Adult; D000368:Aged; D016232:Endothelins / Q000097:blood*; D004958:Estradiol / Q000097:blood; D015914:Estrogen Replacement Therapy; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood*; D017698:Postmenopause / Q000097:blood*
D016232:Endothelins; D009569:Nitric Oxide; D004958:Estradiol; D005640:Follicle Stimulating Hormone