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Effects of the menopause, gender, and estrogen replacement therapy on vascular nitric oxide activity

Lookup NU author(s): Dr Nikhil Majmudar, Professor Steve Robson, Professor Gary Ford

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Abstract

Changes in vascular nitric oxide (NO) activity may contribute to cardiovascular risk. We determined the effect of the menopause, gender, and estrogen replacement therapy on arterial vascular NO activity. Vascular NO activity and sensitivity were determined in 15 healthy premenopausal women (mean age, 48 yr), 12 postmenopausal women (51 yr), and 14 men (51 yr). The effects of 14 days of estrogen replacement therapy (625μg conjugated estrogens) were studied in 20 healthy postmenopausal women (60 yr). Forearm blood flow responses to brachial arterial infusions of L-NG-monomethyl-arginine (L-NMMA), norepinephrine, glyceryl trinitrate (GTN), and serotonin were determined using venous occlusion plethysmography. Constrictor responses to L-NMMA were reduced in postmenopausal women (82 ± 14, summary response, mean ± SEM) and men (89 ± 6) compared to premenopausal women (118 ± 10; P < 0.05). Constrictor responses to norepinephrine were increased in males (125 ± 13) compared to premenopausal (81 ± 8) and postmenopausal (88 ± 16) women (P < 0.05). No differences were observed in GTN or serotonin responsiveness. Constrictor responses to L-NMMA increased after estrogen replacement (132 ± 7 vs. 89 ± 14; P < 0.05), with no change in norepinephrine, GTN, or serotonin responses. The menopause and male gender were associated with reduced arterial NO activity. Two weeks of estrogen replacement therapy restored vascular NO activity to premenopausal levels. Changes in vascular NO activity may contribute to changes in cardiovascular risk associated with male gender, postmenopausal status, and estrogen replacement therapy. Increased α-adrenoceptor responsiveness may contribute to increased cardiovascular risk in males.


Publication metadata

Author(s): Robson SC; Ford GA; Majmudar NG

Publication type: Article

Publication status: Published

Journal: Journal of Clinical Endocrinology and Metabolism

Year: 2000

Volume: 85

Issue: 4

Pages: 1577-1583

ISSN (print): 0021-972X

ISSN (electronic): 1945-7197

Publisher: The Endocrine Society

URL: http://dx.doi.org/10.1210/jc.85.4.1577

DOI: 10.1210/jc.85.4.1577

PubMed id: 10770200


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