Blood Pressure and Hormonal Changes Following Alteration in Dietary Sodium and Potassium in Mild Essential Hypertension

Parfrey, Patrick S.; Wright, Philip L.; Goodwin, F. J.; Vandenburg, M. J.; Holly, Jeffrey M P; Evans, Stephen; Ledingham, J. M.

doi:10.1016/s0140-6736(81)90001-5

Cited by 83 publications

(28 citation statements)

References 19 publications

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“…12227 - 34 Unfortunately, these studies are inconclusive. Small numbers of subjects, 1 26 ' "• 3133 study design limit the usefulness of published human trials.…”

Section: Potassium In the Treatment Of Hypertension/sveffery Et Almentioning

confidence: 99%

Double-blind, placebo-controlled trial of potassium chloride in the treatment of mild hypertension.

LP¹,

Yarger²,

Feussner³

et al. 1987

Hypertension

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With the technical assistance of Toby S. BrownSUMMARY Epidemiologies! and experimental data suggest blood pressure-lowering effects of dietary potassium. A randomized, double-blind clinical trial was used to assess blood pressure response to orally administered potassium, 120 mEq/day, and to placebo in 101 adults with mild hypertension. Blood pressure was measured with a random-zero sphygmomanometer every 2 weeks of this 8-week trial. Systolic blood pressure in the potassium-treated group decreased by 6.4 ± 13.7 (SD) mm Hg ( p < 0.025) compared with 0.11 ± 13.0 mm Hg in the placebo-treated group (p = 0.96). Diastolic blood pressure in the potassium-treated group decreased by 4.1 ± 8.3 mm Hg (p<0.05) compared with a 1.6 ± 6.5 mm Hg decrease in placebo-treated subjects (p= 0.09). Baseline blood pressure of potassium-treated subjects was unexpectedly higher than that of controls. After correcting for baseline variation, blood pressure still decreased 3.4/1.8 mm Hg more in potassium recipients than in placebo recipients (p = 0.14 and 0.24, respectively). Blood pressure decreased by 19/13 mm Hg in five blacks taking potassium vesus a 1/0 mm Hg increase in seven blacks taking placebo. Compliance with the potassium regimen was 91.5% by pill count; only one subject discontinued treatment because of side effects. In conclusion, 120 mEq/day of microencapsulated potassium chloride was well tolerated in adults with mild hypertension. An antihypertensive effect of potassium cannot be ruled out despite the fact that there was no statistically significant difference between potassium-treated and placebo-treated subjects after adjustment for differences in baseline blood pressure. Systolic blood pressure was affected more than diastolic blood pressure. Blacks may be particularly sensitive to blood pressure-lowering effects of potassium chloride. A larger clinical trial stratified by baseline blood pressure and race is required. (Hypertension 9: 444- In experimental models of renovascular, genetic, and salt-sensitive hypertension, high potassium intake has been shown to attenuate the development of hyper-

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“…12227 - 34 Unfortunately, these studies are inconclusive. Small numbers of subjects, 1 26 ' "• 3133 study design limit the usefulness of published human trials.…”

Section: Potassium In the Treatment Of Hypertension/sveffery Et Almentioning

confidence: 99%

Double-blind, placebo-controlled trial of potassium chloride in the treatment of mild hypertension.

LP¹,

Yarger²,

Feussner³

et al. 1987

Hypertension

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“…However, with the introduction of sensitive radioenzymatic assays for measurement of circulating catecholamines, a number of recent studies have indicated that such measurements can provide a reliable index of sympathetic activity under certain conditions, [1][2][3][4][5][6][7][8][9][10][11][12] particularly when factors such as body posture,26 age,27 smoking,28 caffeine consumption,29 stress,30 exercise,-medications, salt intake,'131 and blood pressure8 32 are taken into account. Much care was thus devoted in the present study to control of the blood sampling procedure, and only normal subjects falling into a restricted age range were studied.…”

Section: Discussionmentioning

confidence: 99%

Transient enhancement of sympathetic nervous system activity by long-term restriction of sodium intake.

1985

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To further investigate the relationship between salt intake and sympathetic nervous system activity, the short-and long-term effects of a low-salt diet (40 meq/day) were assessed in 10 normal subjects. Measurements of hemodynamic, hormonal, and other parameters were obtained on the day preceding institution of the low-salt diet (day 0) and on days 4, 7, 30, and 60 of the diet. Urinary sodium excretion was 178 1 0 meq/24 hr on day 0 and 31 ± 4, 38 4, 45 ± 6, and 47 + 7 meq/24 hr on days 4, 7, 30, and 60, respectively (all p < .001 compared with day 0). Blood pressure, urinary potassium, serum electrolytes, and cardiac function (as assessed by echocardiography) were not modified by the 2 month low-salt diet. Plasma renin activity and plasma aldosterone were significantly elevated above control values throughout the entire period of the low-salt diet. In contrast, plasma norepinephrine concentration increased significantly only on days 4 and 7 (from 253 ± 20 pg/ml on day 0 to 495 ± 32 pg/ml, p < .001, and 347 + 22 pg/ml, p < .05, respectively), returning to baseline at days 30 (280 ± 18 pg/ml) and 60 (262 + 18 pg/ml). Changes in plasma epinephrine paralleled those observed for norepinephrine. Similarly, resting heart rate and the blood pressure response to isometric exercise were significantly increased only on days 4 and 7 of the low-salt diet. These results suggest that sympathetic nervous system activity is enhanced only transiently during a sustained reduction in sodium intake. Circulation 72, No. 1, 47-52, 1985. IT HAS LONG been hypothesized that the level of sodium intake affects sympathetic nervous system activity both in normal and in hypertensive subjects. There have been several reports that circulating catecholamines increase during dietary sodium restriction'`8 and decrease upon sodium loading,3' 6-9 although some conflicting data exist. ' sensitivity to norepinephrine while it decreases the basal plasma concentration of norepinephrine, ' but others have found no change in renal vascular reactivity to norepinephrine during acute sodium repletion.'9 These discrepancies could be ascribed to differences in the experimental protocols used in the studies, such as differences in animal species used or clinical characteristics of the population studied (e.g., with respect to age, blood pressure) and differences in the duration and degree of the changes in salt intake.The purpose of the present study was to assess the time course of the humoral and hemodynamic responses to a moderate reduction in sodium intake, particularly as related to sympathetic nervous system activity, in a homogeneous group of normal human subjects. MethodsTwelve normal volunteer subjects from 23 to 39 years old (mean + SEM = 35 ± 3.5 years) were enrolled in the study. As a group they had no history of serious illness and no family history of hypertension. Informed written consent was obtained from each and they took no drugs for the duration of the study. To achieve an equilibrium on a standardized diet for baseline measureme...

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“…Lake et al 9 found that the plasma NE of hypertensive patients was higher and explained that this was due to the fact that their hypertensive patients were older than their nonnotensive subjects. Battabee et al 24 and Parfrey et al 25 reported that the amount of potassium intake had a much greater influence on plasma NE levels than sodium intake. Goldstein 4 "* suggested that the differences in plasma NE may be caused by incomplete age-matching, amounts of sodium or potassium intake, and technical problems in the analysis of plasma catecholamines.…”

Section: Figure 3 Epinephrine (E) Le\>els Of Hypertensive Patients (mentioning

confidence: 98%

Increased plasma norepinephrine in young patients with essential hypertension under three sodium intakes.

Masuo¹,

Ogihara²,

Kumahara³

et al. 1984

Hypertension

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SUMMARY Increased sympathetic nerve activity may play an important role in the pathogenesis of essential hypertension. It is well known that both dietary sodium intake and age influence the plasma norepinephrine (NE) concentration. The present study was undertaken to evaluate the effects of age on sympathetic nerve activity in patients with essential hypertension and normal control subjects under low-, regular-, and high-sodium regimens (mean 24-hour sodium excretions: 30 ± 4,116 ± 7, 280 ± 15 mEq, respectively). Plasma NE and eplnephrine (E) were analyzed by trihydroxyindole methods after high-performance liquid chromatography separation. Subjects were categorized by age into young (^40 yrs), middle-aged (40-60 years), and old (>60 years) subgroups. Mean plasma NE in hypertensive patients was significantly higher (p < 0.01) than in normal subjects on each of the sodium regimens. In normal control subjects, there was a significant positive correlation between age and plasma NE with all three sodium intakes. However, no correlation was seen in hypertensive patients on any of the sodium regimens, because in the young subgroup of hypertensive patients the mean plasma NE was significantly higher than that of normal control subjects. These results suggest that the increased sympathetic nerve activity plays an important role in the pathogenesis of essential hypertension, especially in young patients. (Hypertension 6: 315-321, 1984) KEY WORDS • essential hypertension urinary sodium excretion age • plasma norepinephrine M ANY studies have focused on the involvement of the sympathetic nervous system in the pathogenesis and development of essential hypertension.13 However, the findings remain controversial.4 " 6 Some investigators 7 -8 have reported increased levels of plasma norepinephrine (NE) and increased excretion of urinary NE in patients with essential hypertension. Others workers 9 "" have reported no change or decrease in these factors. Reports on the relationship between age and plasma NE are also inconsistent. Some investigators have shown an elevation of plasma NE with aging in normal subjects, and/ or patients with essential hypertension. 9101213 It is also well known that the amount of sodium intake influences plasma NE levels.'*~17 There are few studies on the relationship between age and plasma NE in normal subjects and patients with essential hypertension under various sodium intakes.From the Department of Medicine and Geriatrics (Drs. Masuo, Ogihara, and Kumahara) and the Second Department of Pharmacology (Drs. Yamatodani and Wada), Osaka University Medical School, Osaka, Japan.Address for reprints: Toshio Ogihara, M.D., Department of Medicine and Geriatrics, Osaka University Medical School, Fukushima-ku, Osaka 553, Japan.Received April 4, 1983; revision accepted October 3, 1983.In this study, we evaluated the influence of age on plasma NE and epinephrine (E) in both normal subjects and patients with essential hypertension under low-, regular-, and high-sodium intake. Materials and Methods SubjectsFo...

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Blood Pressure and Hormonal Changes Following Alteration in Dietary Sodium and Potassium in Mild Essential Hypertension

Cited by 83 publications

References 19 publications

Double-blind, placebo-controlled trial of potassium chloride in the treatment of mild hypertension.

Double-blind, placebo-controlled trial of potassium chloride in the treatment of mild hypertension.

Transient enhancement of sympathetic nervous system activity by long-term restriction of sodium intake.

Increased plasma norepinephrine in young patients with essential hypertension under three sodium intakes.

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