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-2 adminis tration on nitric oxide (NO) plasma levels in postmenopausal women. De sign: Randomized, placebo-controlled trial. Setting: Healthy volunteer s in an academic research environment. Patient(s): Twenty-eight health y postmenopausal women. Intervention(s): Transdermal administration of E-2 (100 mu g/d) or placebo on days 1 and 4 of a 1-week treatment reg imen. Main Outcome Measure(s): Serum concentrations of E-2 and plasma concentrations of NO stable oxidation products were assessed on day I, 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-2 group (40.08 +/- 15.42 mu mol/L , 38.05 +/- 18.82 mu mol/L, and 42.03 +/- 16.81 mu mol/L on days 2, 3, and 6, respectively) compared with both baseline levels (23.07 +/- 5. 79 mu mol/L) and the placebo group (23.51 +/- 4.06 mu mol/L, 21.64 +/- 4.72 mu mol/L, and 21.81 +/- 4.46 mu mol/L on days 2, 3, and 6, respe ctively). Conclusion(s): During a I-week treatment regimen with transd ermal E-2, plasma levels of NO in postmenopausal women were significan tly higher than baseline levels on days 2, 3, and 6. This suggests tha t the effect of estrogens on NO synthesis is rapid and that it is main tained with repeated administration. (C) 1998 by American Society for Reproductive Medicine.