Hormone replacement therapy and 24-hour blood pressure profile of postmenopausal women

Butkevich, Alexander; Abraham, Carmella; Phillips, Robert A.

doi:10.1016/s0895-7061(00)00284-3

Cited by 49 publications

(32 citation statements)

References 14 publications

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“…increase nocturnal dipping in postmenopausal women (9,10,29). Collectively, the current and previous studies suggest that gonadal steroids enhance the diurnal variation in cardiovascular regulation.…”

Section: Discussionsupporting

confidence: 65%

Baroreflex sensitivity varies during the rat estrous cycle: role of gonadal steroids

Goldman¹,

Azar²,

Mulvaney³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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-Baroreflex sensitivity (BRS) increases in women during the luteal phase of the menstrual cycle, when gonadal hormones are elevated, but whether a similar cycle-dependent variation in BRS occurs in rats is unknown. In addition, whether cyclic BRS changes depend on gonadal steroids has not been previously investigated. To test these hypotheses, BRS was determined in cycling female rats using two approaches: 1) baroreflex control of renal sympathetic nerve activity (RSNA) in anesthetized rats; 2) cardiovagal spontaneous BRS (sBRS) in conscious rats instrumented for continuous telemetric measurements of mean arterial pressure (MAP) and heart rate (HR). MAP, HR, and sBRS were also measured in rats 2-3 and 5-6 wk following ovariectomy (OVX), to eliminate gonadal steroids. In anesthetized rats, RSNA BRS gain was increased (P Ͻ 0.01) during proestrus (Ϫ4.8Ϯ0.5% control/mmHg) compared with diestrus/estrus (Ϫ2.8 Ϯ 0.3% control/mmHg). Similarly, a proestrous peak in sBRS was observed in conscious rats (1.66 Ϯ 0.07 ms/mmHg, proestrus; 1.48 Ϯ 0.06 ms/mmHg, diestrus/ estrus; P Ͻ 0.001). OVX eliminated estrous cycle-induced variation in sBRS. In addition, OVX reduced (P Ͻ 0.05) diurnal variations in MAP (5.9 Ϯ 0.3 vs. 3.9 Ϯ 0.5 mmHg) and HR [54 Ϯ 4 vs. 39 Ϯ 3 beats per minute (bpm)], and abolished diurnal variations in sBRS. Finally, while MAP, HR, and sBRS were decreased 2-3 wk following OVX, ϳ3 wk later, MAP and sBRS increased, and HR decreased further. No changes in MAP, HR, or sBRS were seen with time in sham OVX controls. In summary, RSNA and cardiovagal sBRS vary during the rat estrous cycle, and this variation is abolished by OVX. We conclude that sex steroid hormones are required for both cyclic and diurnal changes in BRS in rats.renal sympathetic nerve activity; ovariectomy; diurnal; telemetry CONSIDERABLE EVIDENCE INDICATES that gonadal steroids can influence mean arterial pressure (MAP), heart rate (HR), and baroreflex sensitivity (BRS). First, sex differences have been documented (1,2,5,16,20,27). Second, MAP and HR vary during the estrous cycle of the rat (53), and, in humans, sympathetic BRS increases during the midluteal phase, when gonadal steroid hormone concentrations are higher, compared with the early follicular phase of the menstrual cycle (32). Nevertheless, whether BRS changes during the rat estrous cycle has not been studied. Moreover, whether changes in gonadal steroids underlie the reproductive cycle variability in MAP, HR, and BRS is unclear. Ovariectomy (OVX) and administration of estrogen and/or progesterone have been shown to alter MAP and HR in women and experimental animals; however, results have been conflicting (12,19,31,36,42,53,58). Furthermore, estrogen increases BRS (25,34,40,47); in contrast, a neurosteroid metabolite of progesterone, allopregnanolone, decreases BRS (18). Thus, a clear understanding of the influence of cyclic changes in endogenous gonadal steroids on MAP, HR, and BRS is lacking.Therefore, the primary goal of this study was to determine if BRS varies during the rat estrou...

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Section: Discussionsupporting

confidence: 65%

Baroreflex sensitivity varies during the rat estrous cycle: role of gonadal steroids

Goldman¹,

Azar²,

Mulvaney³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Some experimental studies have demonstrated an increase in vascular distensibility, as well as an increase in FBF, after estrogen administration (20,42,63). In addition, a number of studies have shown that estrogen therapy results in lower blood pressure (4,5,12). However, in the present study, estrogen therapy did not alter blood pressure, MSNA, blood flow, or vascular resistance.…”

Section: Discussioncontrasting

confidence: 63%

“…Among previously normotensive women treated with hormone replacement therapy, blood pressure has been shown to decrease (4,5), increase (67,70), and be unaffected (57,60,66). Similarly, studies have shown hormone replacement therapy to reduce heart rate (HR) significantly (31,68), whereas others have shown that it has no effect on HR (51,68).…”

mentioning

confidence: 99%

Low-dose estrogen therapy does not change postexercise hypotension, sympathetic nerve activity reduction, and vasodilation in healthy postmenopausal women

Oneda

Forjaz²,

Bernardo³

et al. 2008

American Journal of Physiology-Heart and Circulatory Physiology

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The aim of this study was to determine whether estrogen therapy enhances postexercise muscle sympathetic nerve activity (MSNA) decrease and vasodilation, resulting in a greater postexercise hypotension. Eighteen postmenopausal women received oral estrogen therapy (ET; n ϭ 9, 1 mg/day) or placebo (n ϭ 9) for 6 mo. They then participated in one 45-min exercise session (cycle ergometer at 50% of oxygen uptake peak) and one 45-min control session (seated rest) in random order. Blood pressure (BP, oscillometry), heart rate (HR), MSNA (microneurography), forearm blood flow (FBF, plethysmography), and forearm vascular resistance (FVR) were measured 60 min later. FVR was calculated. Data were analyzed using a two-way ANOVA. Although postexercise physiological responses were unaltered, HR was significantly lower in the ET group than in the placebo group (59 Ϯ 2 vs. 71 Ϯ 2 beats/min, P Ͻ 0.01). In both groups, exercise produced significant decreases in systolic BP (145 Ϯ 3 vs. 154 Ϯ 3 mmHg, P ϭ 0.01), diastolic BP (71 Ϯ 3 vs. 75 Ϯ 2 mmHg, P ϭ 0.04), mean BP (89 Ϯ 2 vs. 93 Ϯ 2 mmHg, P ϭ 0.02), MSNA (29 Ϯ 2 vs. 35 Ϯ 1 bursts/min, P Ͻ 0.01), and FVR (33 Ϯ 4 vs. 55 Ϯ 10 units, P ϭ 0.01), whereas it increased FBF (2.7 Ϯ 0.4 vs. 1.6 Ϯ 0.2 ml ⅐ min Ϫ1 ⅐ 100 ml Ϫ1 , P ϭ 0.02) and did not change HR (64 Ϯ 2 vs. 65 Ϯ 2 beats/min, P ϭ 0.3). Although ET did not change postexercise BP, HR, MSNA, FBF, or FVR responses, it reduced absolute HR values at baseline and after exercise. postmenopause; aerobic exercise; muscle sympathetic nerve activity; blood pressure THE POSTMENOPAUSAL PERIOD is accompanied by a number of physiological alterations (49). In postmenopausal women, blood pressure gradually increases (71), resulting in a considerably higher incidence of hypertension than that seen in premenopausal women (68). This difference has been attributed to abnormalities in arteriolar resistance caused by the absence of estrogen (48) and/or by physiological aging (1). Arteriolar resistance and hypertension are usually associated with an increase in sympathetic activity or responsiveness (33,64). However, the effects of menopause on sympathetic activity remain unclear. One recent study evaluated Polish and American women between 40 and 56 yr of age (50). The authors found that sympathetic activity in the postmenopausal women was similar to that observed in the premenopausal women. In contrast, the authors of a study conducted in Japan (46) observed higher sympathetic nerve activity in post-and premenopausal middle-aged women. Discrepancies in results might be related to many factors, such as ethnic background and diet.Postmenopausal women are often treated with hormone replacement therapy to minimize the symptoms and consequences of menopause. However, the effects of this therapy depend on the type and dose of hormone employed (31). Currently, many women are receiving natural estrogens, and the North American Menopause Society recommends that hormone replacement therapy should be administered in low doses to avoid any possible side effects (...

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“…On the other hand, the exclusion of females may help to avoid circadian variation of BP mainly related to oral contraceptives, hormone replacement, and menopause. 38,39 Second, our sample size is relatively small to detect differences in some parameters such as frequency of nondipping or the magnitude of the BP decrease in patients with and without masked hypertension after CPAP treatment. The significant fall in all BP variables derived from 24-hour ABPM and not in the office diastolic BP may be related to the small sample size.…”

Section: Drager Et Al Osa Prehypertension and Masked Hypertensionmentioning

confidence: 99%

The Effects of Continuous Positive Airway Pressure on Prehypertension and Masked Hypertension in Men With Severe Obstructive Sleep Apnea

et al. 2011

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Abstract-Obstructive sleep apnea and hypertension are common conditions that frequently coexist. Continuous positive airway pressure (CPAP) reduces blood pressure in patients with obstructive sleep apnea and sustained hypertension. However, the impact of CPAP on patients with obstructive sleep apnea and prehypertension and masked hypertension, conditions associated with increased cardiovascular risk, is unknown. Thirty-six male patients (age, 43Ϯ7 years; body mass index, 28.8Ϯ3.0 kg/m 2 ) with untreated severe obstructive sleep apnea (apnea-hypopnea index, 56Ϯ22 events/hr on polysomnography) with diagnostic criteria for prehypertension and/or masked hypertension, based on office and 24-hour ambulatory blood pressure monitoring, respectively, were studied. The patients randomized to no treatment (control; nϭ18) or CPAP (nϭ18) for 3 months had similar frequency of prehypertension and masked hypertension at study entry. There were no significant changes in blood pressure in patients randomized to the control group. In contrast, patients randomized to CPAP presented significant reduction in office systolic (from 126Ϯ5 to 121Ϯ7 mm Hg; Pϭ0.001) and a trend for diastolic blood pressure (from 75Ϯ7 to 73Ϯ8 mm Hg; Pϭ0.08) as well as a significant decrease in daytime and nighttime systolic and diastolic blood pressure (PϽ0.05 for each comparison). There was a significant reduction in the frequency of prehypertension (from 94% to 55%; Pϭ0.02) and masked hypertension (from 39% to 5%; Pϭ0.04) only in the CPAP group. In conclusion, effective CPAP therapy promotes significant reduction in the frequency of prehypertension and masked hypertension by promoting significant blood pressure reductions in patients with severe obstructive sleep apnea.

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Hormone replacement therapy and 24-hour blood pressure profile of postmenopausal women

Cited by 49 publications

References 14 publications

Baroreflex sensitivity varies during the rat estrous cycle: role of gonadal steroids

Baroreflex sensitivity varies during the rat estrous cycle: role of gonadal steroids

Low-dose estrogen therapy does not change postexercise hypotension, sympathetic nerve activity reduction, and vasodilation in healthy postmenopausal women

The Effects of Continuous Positive Airway Pressure on Prehypertension and Masked Hypertension in Men With Severe Obstructive Sleep Apnea

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