Long-term effects of ovariectomy and estrogen replacement treatment on endothelial function in mature rats

Moien‐Afshari, Farzad; Kenyon, Emma J.; Choy, Jonathan C.; Battistini, Bruno; McManus, Bruce M.; Laher, Ismail

doi:10.1016/s0378-5122(03)00149-x

Cited by 34 publications

(30 citation statements)

References 43 publications

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“…For example, it was demonstrated that long-term estrogen replacement therapy increased vasodilation in response to ischemia in the forearm resistance arteries in postmenopausal women (26), and it was demonstrated that ovariectomy of rats caused a loss of acetylcholine-mediated dilation within weeks (27). However, to fully appreciate the interaction between estrogen and glycine observed in this study, it is necessary to further explore the mechanisms underlying the vascular effects of estrogen and glycine.…”

Section: Discussionmentioning

confidence: 82%

Decreases in Renal Functional Reserve and Proximal Tubular Fluid Output in Conscious Oophorectomized Rats

Nielsen¹,

Flyvbjerg²,

Bruun³

et al. 2003

Journal of the American Society of Nephrology

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Abstract. Age-dependent glomerulosclerosis with reduced GFR develops earlier among men than among women. Therefore, whether female sex hormones could prevent the agedependent decrease in GFR was investigated. The kidney function in oophorectomized rats treated with placebo (OOX group), estrogen (OOXϩE 2 group), or estrogen plus progesterone (OOXϩE 2 ϩP group) for 5 mo and in sham-operated rats (sham group) was examined. The rats were 13 mo of age at the time of the investigation. They were conscious and chronically instrumented. The results demonstrated that estrogen, alone or in combination with progesterone, was without effect on the baseline GFR and effective renal plasma flow but prevented severe decreases in the renal functional reserve and fractional proximal tubular fluid output (lithium clearance technique, fractional lithium excretion), which were observed in the OOX group. The renal functional reserve (estimated by stimulation with glycine) was Ϫ223 Ϯ 151, 483 Ϯ 129, 675 Ϯ 76, and 208 Ϯ 140 l/min in the OOX, OOXϩE 2 , OOXϩE 2 ϩP, and sham groups, respectively. Fractional lithium excretion was 12.4 Ϯ 3.1, 26.8 Ϯ 2.0, 31.8 Ϯ 2.5, and 23.6 Ϯ 3.3% in the OOX, OOXϩE 2 , OOXϩE 2 ϩP, and sham groups, respectively. In conclusion, oophorectomy at the age of 8 mo did not produce a decrease in baseline GFR in female rats within a period of 5 mo. However, oophorectomy led to severe decreases in the renal functional reserve and fractional proximal tubular fluid output. Both effects were prevented with administration of estrogen. Sham-operated rats demonstrated values for renal functional reserve and fractional lithium excretion that were between those observed for the OOX group and the groups treated with sex hormones.

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Section: Discussionmentioning

confidence: 82%

Decreases in Renal Functional Reserve and Proximal Tubular Fluid Output in Conscious Oophorectomized Rats

Nielsen¹,

Flyvbjerg²,

Bruun³

et al. 2003

Journal of the American Society of Nephrology

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“…Furthermore, the persistent estrus (constant sexual receptivity) observed in aged female rats suggests an incomplete suppression of sex hormones with aging see. 22 In the present study, female rats were OVX at 10 weeks of age, and the physiologic measurements were performed 9 weeks later. The incidence of CVD in women increases sharply after menopause 23 and probably involves changes in AP and its regulation associated with estrogen loss.…”

Section: Discussionmentioning

confidence: 99%

“…Because there are no rat models of menopause that are considered ideal, most investigators have used relatively young (6 to 12 weeks) female rats OVX for short periods (3 to 5 weeks). 22 Although this model may not be appropriate to determine long-term changes in CV regulation during menopause, the OVX procedure is an efficient way to simulate menopause status, because it suppresses ovarian hormonal levels. Furthermore, the persistent estrus (constant sexual receptivity) observed in aged female rats suggests an incomplete suppression of sex hormones with aging see.…”

Section: Discussionmentioning

confidence: 99%

Exercise Training Improves Baroreflex Sensitivity Associated With Oxidative Stress Reduction in Ovariectomized Rats

Irigoyen

Paulini²,

Flores³

et al. 2005

Hypertension

104

130

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Abstract-The protection from coronary events that young women have is sharply reduced at menopause. Oxidative stress and baroreflex sensitivity impairment of the circulation have been demonstrated to increase cardiovascular risk. On the other hand, exercise training has been indicated as a nonpharmacological treatment for many diseases. The aim of the present study was to test the hypothesis that exercise training can improve baroreflex sensitivity associated with reduction in oxidative stress in ovariectomized rats, an experimental model of menopause. Exercise training was performed on a treadmill for 8 weeks. Arterial pressure and baroreflex sensitivity, which were evaluated by tachycardic and bradycardic responses to changes in arterial pressure, were monitored. Oxidative stress was evaluated by chemiluminescence and superoxide dismutase and catalase antioxidant enzyme activities. Exercise training reduced resting mean arterial pressure (112Ϯ2 vs 122Ϯ3 mm Hg in the sedentary group) and heart rate (325Ϯ4 vs 356Ϯ12 bpm in the sedentary group) and also improved baroreflex sensitivity (tachycardic response, 63% and bradycardic response, 58%). Myocardium (25%) and gastrocnemius muscle (48%) chemiluminescence were reduced, and myocardial superoxide dismutase (44%) and gastrocnemius catalase (97%) activities were enhanced in trained rats in comparison with sedentary rats. Myocardium chemiluminescence was positively correlated with systolic arterial pressure (rϭ0.6) and inversely correlated with baroreflex sensitivity (tachycardic response, rϭϪ0.8 and bradycardic response, rϭϪ0.7). These results indicate that exercise training in ovariectomized rats improves resting hemodynamic status and reflex control of the circulation, probably associated with oxidative stress reduction, suggesting a homeostatic role for exercise training in reducing cardiovascular risk in postmenopausal women. Key Words: exercise Ⅲ baroreflex Ⅲ oxidative stress Ⅲ rat Ⅲ estrogen Ⅲ menopause M enopause has been associated with impairment of aerobic fitness, muscle strength, and bone mineral density, as well as an increase in body weight, type 2 diabetes, osteoporotic fractures, and cardiovascular disease (CVD). 1 Many CVD states are associated with baroreflex impairment, the most important short-term regulator of arterial blood pressure. Moreover, the baroreflex has been recognized as a marker of autonomic control and as a predictor of CV mortality. 2 Estrogen deprivation induces endothelial dysfunction and autonomic impairment and increases oxidative stress in fertile young women 3 and postmenopausal women, 4,5 thus increasing the CV risk. Oxidative stress has been implicated in the pathophysiology of a large number of diseases, and it plays a possible mechanistic role in baroreflex dysfunction, because antioxidant substances seem to improve baroreflex sensitivity (BRS) in different species. 6 -9 However, the role of oxidative stress on CV autonomic dysfunction during estrogen deprivation is not well understood.Since the Women's Health Initiative...

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“…Only later in life, old rodents will experience low levels of estrogen and progesterone and little or no remaining ovarian follicle (Felicio et al, 1984;Lu et al, 1979). In this regard, the cardiovascular effects of estrogen in Lekontseva et al, 2010;Moien-Afshari et al, 2003).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Gathering of aging and estrogen withdrawal in vascular dysfunction of senescent accelerated mice

Novella

Dantas

Segarra

et al. 2010

Experimental Gerontology

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of aging and estrogen withdrawal in vascular dysfunction of senescent accelerated mice. Experimental Gerontology, Elsevier, 2010, 45 (11) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

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Long-term effects of ovariectomy and estrogen replacement treatment on endothelial function in mature rats

Cited by 34 publications

References 43 publications

Decreases in Renal Functional Reserve and Proximal Tubular Fluid Output in Conscious Oophorectomized Rats

Decreases in Renal Functional Reserve and Proximal Tubular Fluid Output in Conscious Oophorectomized Rats

Exercise Training Improves Baroreflex Sensitivity Associated With Oxidative Stress Reduction in Ovariectomized Rats

Gathering of aging and estrogen withdrawal in vascular dysfunction of senescent accelerated mice

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