Nitric oxide in postmenopausal women taking three different HRT regimens.

Objective: To search and compare the effects of three different HRT regimens on nitric oxide levels of postmenopausal women.

Methods: Four groups of postmenopausal women were included in this prospective, randomised, placebo controlled study. 34 women used 0.625 mg conjugated estrogen continuously combined with 5 mg medroxyprogesterone acetate, 32 women used 2.5 mg tibolone, 26 women used 50 mcg transdermal estrogen alone continuously and 32 women used placebo for 12 months. Before the treatment and after 1 year, serum NO (nitrate/nitrite) and some other biochemical parameters were evaluated.

Results: All HRT using groups had increased serum nitric oxide levels significantly compared to placebo group and also there was not any difference among three HRT using groups concerning to increases in nitric oxide levels.

Conclusion: Both conjugated estrogen combined with continuous progestin and transdermal estrogen alone and also tibolone increases serum nitric oxide levels of postmenopausal women equally for 12-months of treatment.