Hormone therapy and asymmetrical dimethylarginine in postmenopausal women.

Women present an estradiol-dependent cardiovascular risk profile. Based on various studies, it was considered that estrogen therapy (ET) in postmenopausal women could probably reduce the higher cardiovascular risk in this group. Assymetric dimethylarginine (ADMA) is an endogenous methylated arginine which inhibits nitric oxide (NO) synthesis by competing with the substrate of NO, L-arginine, leading to endothelial dysfunction and, consequently, to atherosclerosis. Moreover, ADMA has been considered as an independent risk factor for cardiovascular disease. It has also been found that hormone therapy (HT), and mainly oral estrogen therapy, lowers ADMA concentrations in healthy postmenopausal women. The effect of estrogens on ADMA levels, although small, is considered important, as physiological variation of ADMA is limited. Nevertheless, larger randomized trials are necessary to establish that estrogens substantially lower ADMA levels and that these changes really reflect improved cardiovascular prognosis in postmenopausal women.