A comparison of effects of sequential transdermal administration versus oral administration of estradiol plus norethisterone acetate on serum NO levels in postmenopausal women

Abstract

Aim To compare the effects of sequential transdermal administration versus oral administration of estradiol plus NETA on serum nitric oxide (NO) levels in postmenopausal women (PMW). Materials and methods Eighty postmenopausal subjects without any prior hormone replacement therapy (HRT) usage were enrolled in this study. All participants were healthy, ambulatory, non-smoker and had similar life styles with dietary habits. HRT was given to participants according to desired HRT administration, in group A ( n = 50); oral estradiol hemi-hydrate (2 mg)/norethisterone acetate (1 mg), and in group B ( n = 30); transdermal combined patch comprising estradiol (0.05 mg) alone and estradiol (0.05 mg)/norethisterone acetate (0.25 mg), were given sequential for 12 months. Serum NO levels were studied using Total Oxide Assay Kit (Assay Designs, Inc.) according to manufacturer's instructions prior to and after 12 months from the HRT treatment. Results The mean serum NO levels prior to the HRT in groups A and B was 0.48 ± 0.46 (range, 0.27–0.76 nmol/mL) nmol/mL and 0.47 ± 0.48 nmol/mL (range, 0.29–0.693 nmol/mL) ( p > 0.05). The mean serum NO levels after the HRT in groups A and B was 0.53 ± 0.33 nmol/mL (range, 0.29–2.10 nmol/mL) and 2.91 ± 0.50 nmol/mL (range, 2.10–3.67 nmol/mL) ( p < 0.05). A significant difference was found between mean serum NO levels prior to and after the treatment in group B ( p < 0.05). Conclusions Transdermal sequential combined HRT with estradiol hemi-hydrate/NETA was found to be superior to sequential combined oral HRT in increasing serum NO levels.