Effects of short-term transdermal estradiol administration on plasma levels of nitric oxide in postmenopausal women.

Objective: To assess the effects of short-term transdermal E, administration on nitric oxide (NO) plasma levels in postmenopausal women. Design: Randomized, placebo-controlled trial. Setting: Healthy volunteers in an academic research environment. Patient(s): Twenty-eight healthy postmenopausal women. Intervention(s): Transdermal administration of E, (100 pg/d) or placebo on days 1 and 4 of a l-week treatment regimen. Main Outcome Measure(s): Serum concentrations of E, and plasma concentrations of NO stable oxidation products were assessed on day 1, before placement of the patch, and subsequently on days 2, 3, and 6. Result(s): The mean concentration of NO metabolites on days 2, 3, and 6 was significantly greater in the E, group (40.08 5 15.42 pmol/L, 38.05 _+ 18.82 pmol/L, and 42.03 5 16.81 pmol/L on days 2, 3, and 6, respectively) compared with both baseline levels (23.07 + 5.79 PmolL) and the placebo group (23.51 2 4.06 PmolIL, 21.64 + 4.72 Fmol/L, and 21.81 2 4.46 pmol/L on days 2, 3, and 6, respectively). Conclusion(s): During a l-week treatment regimen with transdermal E,, plasma levels of NO in postmenopausal women were significantly higher than baseline levels on days 2, 3, and 6. This suggests that the effect of estrogens on NO synthesis is rapid and that it is maintained with repeated administration. (Fertil SteriP 1998;69:58-61. 01998 by American Society for Reproductive Medicine.

Variation in nitric oxide production induced by HRT

.Cagliari (Forte Village, Santa Margherita di Pula)

Acute effects of transdermal estradiol administration on plasma levels of NO in postmenopausal women

Objective: To investigate the acute effects of transdermal E2 administration on nitric oxide {NO} plasma levels in postmenopausal women. Design: Randomized, placebo-controlled trial. Setting: Normal human volunteers in an academic research environment. Patient(s): Twenty healthy postmenopausal women. Intervention(s): Transdermal administration of 100 pg/d E2 or placebo. Main Outcome Measure(s): Plasma concentrations of NO stable oxidation products and serum concentrations of E._,were assessed before and 24 hours after the administration. Result(s): In the group treated with E2 mean concentration of NO metabolites 24 hours after patch application (37.31 +_7.62 pmol/L) resulted significantly higher than baseline (21.04 ___5.71 pmol/L) and the control group/23.50 _+4.03 pmol/L). The correlation between the mean percent increase in NO metabolites and absolute E., concentrations 24 hours after the E.~administration was statistically significant. Conclusion(s): Transderma] administration of E2 to healthy postmenopausal women in- creases the plasma levels of NO and this supports the hypothesis that a NO-related mechanism may contribute to the cardiovascular protective effect of estrogens in postmenopause