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OBJECTIVE: To evaluate the effects of soy germ isoflavones and hormone therapy on vascular reactivity, the formation of nitric oxide derivatives, and lipid peroxidation in hypercholesterolemic postmenopausal women. DESIGN: Women were treated with soy germ, 17beta-estradiol or 17beta-estradiol + noretisterone acetate for 3 months after taking placebo for 1 month. The plasma concentrations of nitrite + nitrate and S-nitrosothiols were evaluated by gaseous phase chemiluminescence; nitrotyrosine, electronegative low-density lipoprotein, and estradiol levels were determined by enzyme-linked immunosorbent assay; cholesterol oxides and isoflavones were determined by gas chromatography and high-performance liquid chromatography, respectively. Vascular reactivity was analyzed by high-resolution ultrasonography. RESULTS: Soy germ isoflavones and hormone therapy induced a decrease in nitrite + nitrate, electronegative low-density lipoprotein, and cholesterol oxides, as well as an increase in S-nitrosothiols. Soy germ isoflavones lowered electronegative low-density lipoprotein, and cholesterol oxides more efficiently than did hormone therapy. Only soy isoflavones inhibited nitrotyrosine formation. A significant improvement of vascular reactivity was only seen in women treated with 17beta-estradiol. CONCLUSIONS: The soy germ isoflavones and 17beta-estradiol, alone or associated with noretisterone acetate, in the doses and forms used here, have similar effects on the bioavailability of nitric oxide. Soy germ treatment inhibited lipid peroxidation more effectively than hormone therapy.

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Objective: To evaluate the effects of soy germ isoflavones and hormone therapy on vascular reactivity, the formation of nitric oxide derivatives, and lipid peroxidation in hypercholesterolemic postmenopausal women. Design: Women were treated with soy germ, 17A-estradiol or 17A-estradiol + noretisterone acetate for 3 months after taking placebo for 1 month. The plasma concentrations of nitrite + nitrate and S-nitrosothiols were evaluated by gaseous phase chemiluminescence; nitrotyrosine, electronegative low-density lipoprotein, and estradiol levels were determined by enzymelinked immunosorbent assay; cholesterol oxides and isoflavones were determined by gas chromatography and high-performance liquid chromatography, respectively. Vascular reactivity was analyzed by high-resolution ultrasonography. Results: Soy germ isoflavones and hormone therapy induced a decrease in nitrite + nitrate, electronegative low-density lipoprotein, and cholesterol oxides, as well as an increase in S-nitrosothiols. Soy germ isoflavones lowered electronegative low-density lipoprotein, and cholesterol oxides more efficiently than did hormone therapy. Only soy isoflavones inhibited nitrotyrosine formation. A significant improvement of vascular reactivity was only seen in women treated with 17A-estradiol. Conclusions: The soy germ isoflavones and 17A-estradiol, alone or associated with noretisterone acetate, in the doses and forms used here, have similar effects on the bioavailability of nitric oxide. Soy germ treatment inhibited lipid peroxidation more effectively than hormone therapy.

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Verificou-se o efeito dos fitoestrógenos da soja e da terapia de reposição hormonal sobre a concentração dos metabólitos do óxido nítrico(NOx), homocisteína e óxidos de colesterol(COx) em mulheres pós-menopausa em mulheres hipercolesterolêmicas que receberam placebo por um mês e posteriormente gérmen de soja (F, n=11), 17 beta estradiol (E, n=12) ou 17 beta estradiol associado ao acetato de noretisterona (E + P, n=11). Determinou-se os Nox e S nitrosotióis por quimioluminiscência em fase gasosa, a homocisteína por eletroforese capilar e os COx por cromatografia gasosa. O gérmen de soja reduziu as concentrações de NOx (34 +- 16 para 22 +- 9µM, p=0,048) e de homocisteína (13 +- 4 para 9 +- 4µM, p+0,036) e aumentou a concentração de S-nitrosotióis (87 +- 45 para 180 +- 92µM, p+ 0,007), em relação ao placebo. Não foi encontrada diferença significativa para as terapias E e E + P sobre os NOx, homocisteína e S-nitrosotióis. A concentração de óxidos de colesterol foi reduzida nos grupos F e E (96,97 +- 41,74 para 28,52 +- 11,47ng/µL, p=0,00002 e 88,7 +- 56,9 para 33,9 +- 15,8ng/µL, p= 0,027, respectivamente). O uso de fitoestrógenos do gérmen da soja reduziu a concentração de homocisteína, aumentou a concentração de S-nitrosotióis e, associada ao 17 beta estradiol, reduziu a formação de Cox. Portanto, estes dados indicam um efeito protetor dos fitoestrógenos em relação à disfunção endotelial e ao risco de aterosclerose na pós-menopausa.

The effect of phytoestrogens and hormone replacement therapy on nitric oxide metabolites (Nox), homocysteine and cholesterol oxides concentration was evaluated in hypercholesterolemic postmenopausal women that received placebo for 1 month followed by soy germen (F, n=11)...

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