Affiliations: Department of Obstetrics and Gynecology, Bronx-Lebanon
Hospital Center-Albert Einstein College of Medicine, Bronx, NY 10457, USA | Department of Obstetrics and Gynecology, Yale School
of Medicine, New Haven, CT 06520, USA
Note: [] Address for correspondence: Prabhudas R. Palan, PhD, Department
of Obstetrics and Gynecology, Bronx-Lebanon Hospital Center-Albert Einstein
College of Medicine, 1650 Grand Concourse, Floor 5, Bronx, NY 10457, USA. Tel.:
+1 718 239 8308; Fax: +1 718 239 8360; E-mail: daspalan@aol.com
Abstract: The present study examines the influence of menopause and hormone
replacement therapy (HRT) on serum levels of coenzyme Q_{10}
and other lipid-soluble antioxidants in normal women. Serum levels of
coenzyme Q_{10}, α-tocopherol,
γ-tocopherol, β-carotene and
lycopene in 50 premenopausal women (not using oral contraceptives), 33 healthy
postmenopausal and 15 postmenopausal women on HRT ("Prempo"; combination of
0.625 mg conjugated estrogen and 2.5 mg medroxyprogesterone acetate) were
measured by high-pressure liquid chromatography. Lipid profiles were also
analyzed. Significantly higher serum coenzyme Q_{10} and
α-tocopherol levels were detected in postmenopausal
compared with premenopausal women (P<0.05,
and < 0.001); whereas, in postmenopausal subjects on HRT, we
detected a significant decrease in coenzyme Q_{10} and
γ-tocopherol levels (P<0.001, and
< 0.05) and increased α-tocopherol
levels (P<0.05). Serum levels of
β-carotene, lycopene, LDL, HDL, cholesterol and
triglyceride were comparable among the study groups. Coenzyme
Q_{10} is postulated to be involved in preventing
cardiovascular disease (CVD) because of its bioenergetics role in the
mitochondrial respiratory chain and its antioxidant properties at the
mitochondrial and extramitochondrial levels. The decrease in serum
concentrations of coenzyme Q_{10}, produced by HRT, may
promote oxygen free radical-induced membrane damage and may, thus alter
cardiovascular risk in postmenopausal women. HRT-induced reductions in
lipid-soluble antioxidant(s) levels, and its potential consequences on CVD,
needs to be further investigated.
