A sensitive radioenzymatic assay for norepinephrine in tissues and plasma

Henry, David P.; Starman, Barbra J.; Johnson, David G.; Williams, Robert H.

doi:10.1016/0024-3205(75)90258-1

Cited by 479 publications

(111 citation statements)

References 8 publications

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“…Of the 330 samples acquired, 10 were discarded because of storage problems. The PNE concentrations were measured by a radioenzymatic assay based on the technique of Henry et al 31 The mean coefficients of interassay and intraassay variation for these determinations were 9.6% and 8.7%, respectively.…”

Section: Plasma Norepinephrine Determinationsmentioning

confidence: 99%

Failure of plasma norepinephrine to consistently reflect sympathetic activity in humans.

Floras¹,

Jones²,

Hassan³

et al. 1986

Hypertension

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SUMMARY To determine whether venous plasma norepinephrine concentrations consistently reflect changes in sympathetic nervous activity, the influence of mental arithmetic, static handgrip, and submaximal bicycle exercise on infra-arterial blood pressure, heart rate, and plasma norepinephrine was studied in 51 subjects with untreated essential hypertension (mean age, 46 years; range, 16-69 years). At rest, plasma norepinephrine was unrelated to age or blood pressure. Mental arithmetic increased mean arterial pressure from 108 ± 18 to 127 ± 18 mm Hg (mean ± S.D.; p<0.001) and heart rate from 69 ± 7 to 93 ± 13 beats/min (p<0.001) but not plasma norepinephrine (547 ± 297 to 518 ± 250 pg/ml). Isometric exercise raised mean arterial pressure from 115 ± 18 to 148 ± 21 mm Hg (p<0.001) and heart rate from 76 ± 9 to 95 ± 13 beats/min (p<0.001) but not plasma norepinephrine (683 ± 253 to 741 ± 253 pg/ml). Bicycle exercise increased mean arterial pressure from 114 ± 20 to 146 ± 26 mm Hg (p< 0.001), heart rate from 77 ± 9 to 128 ± 19 beats/min (p< 0.001), and plasma norepinephrine from 645 ± 228 to 1151 ± 462 pg/ml (p<0.001). Both the maximum mean arterial pressure and the peak heart rate attained during bicycle exercise were related to the exercise plasma norepinephrine level (r = 0.33, p<0.02 and r=0.28, p<0.03, respectively). Increases in plasma norepinephrine with exercise were not greater in older or more hypertensive subjects. In fact, the relative rise in mean arterial pressure and the absolute increase in plasma norepinephrine during cycling were greater in those with lower resting blood pressures. As only bicycle exerdse increased plasma norepinephrine, and as there was no direct relationship between plasma norepinephrine and arterial blood pressure in subjects studied supine, seated, and during these three activities, we conclude that plasma norepinephrine concentrations do not consistently reflect variations in sympathetic neuronal activity and therefore are relatively insensitive measures of sympathetic tone in humans. Received March 25, 1985; accepted January 21, 1986. Norepinephrine concentration in the venous drainage of an organ is also proportional to the rate of stimulation of its nerves. 3 In humans, physical and emotional stimuli that increase blood pressure and heart rate (HR) also increase PNE. "7 Conversely, concentrations of this catecholamine may be reduced in subjects with autonomic nervous dysfunction 8 or lowered by drugs that interfere with the action of the sympathetic nervous system. 9 Watson et al., 6 who recorded PNE and blood pressure in hypertensive subjects while they slept, lay quietly, woke, stood, walked, and cycled, described a log-linear relationship between PNE and systolic blood pressure during these activities, which suggests that PNE concentrations indeed reflect changes in sympathetic activity.Although increases in PNE with exertion may be greater in some subjects with essential hypertension, 10

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Section: Plasma Norepinephrine Determinationsmentioning

confidence: 99%

Failure of plasma norepinephrine to consistently reflect sympathetic activity in humans.

Floras¹,

Jones²,

Hassan³

et al. 1986

Hypertension

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“…17 Norepinephrine was measured in plasma and urine by a radioenzymatic assay. 28 Analysis of variance, two-tailed t test, and regression analysis were performed by means of a computerized statistical program as appropriate." Since the control subjects were not matched to the first-degree relatives of hypertensives prior to the performance of the protocol, paired f test comparisons were avoided.…”

Section: Protocolmentioning

confidence: 99%

An approach to the evaluation of genetic influences on factors that regulate arterial blood pressure in man.

Grim¹,

Luft²,

Miller³

et al. 1980

Hypertension

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SUMMARY To assess the influence of heredity on factors that help regulate the arterial blood pressure in man, we conducted sodium-loading and depletion studies in monozygotic and dizygotic twins, normotensive first-degree relatives of essential hypertensives, and in nonnotenslve control subjects matched for age, sex, and race. Following sodium-loading, we found evidence for the influence of genetic variance on the natriuretic responses, plasma renin activity (PRA), plasma aldosterone concentrations (PA), and plasma and urinary norepinephrine. Relatives of hypertensives differed from controls in that they had higher blood pressures, greater renin values, and relatively sluggish natriuretic responses. Since renin and fractional sodium excretion values were inversely correlated in all subject groups, it is possible that the heritable influences we observed on sodium excretion were mediated by the renin-angiotensin-aldosterone system. 79 the nature of these influences has not been defined clearly. To examine inherited mechanisms that may contribute to the development of essential hypertension in some individuals, or the resistance to hypertension in others, we conducted detailed studies of monozygotic and dizygotic normotensive twins, normotensive firstdegree relatives of essential hypertensives, and large numbers of normotensive white and black subjects by means of a standardized protocol incorporating both sodium-loading and depletion. "14 In these studies we examined electrolyte balance, components of the renin-angiotensin-aldosterone system, and humoral indicators of sympathetic nervous system activity. The studies in twins 1-34fluences in each of these areas. The studies in normotensive, first-degree relatives of essential hypertensives indicated the existence of important differences in electrolyte excretion and peripheral renin values that may contribute to the susceptibility to hypertension of this high-risk group." We present these findings in light of their bearing on the importance of heredity in regulating blood pressure in man. Methods Studies in TwinsData from monozygotic (MZ) and dizygotic (DZ) twins provide a unique opportunity to test for the existence of genetic variation in traits. Since MZ twins are genetically identical and DZ twins are related as full siblings, a given trait would be expected to exhibit smaller twin-pair differences for MZ than DZ twins if genetic influences are present. On the other hand, if the trait is only influenced by environmental variability, the MZ and DZ twin-pair differences should be approximately equal.The statistical methods involved in the analysis of MZ and DZ twin data have been recently reviewed by Christian. 16 We chose the comparison of MZ and DZ twins as the most efficient method for the initial investigation of heritable components in quantitative by guest on May 11, 2018 http://hyper.ahajournals.org/ Downloaded from

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“…Supine plasma renin activity was measured using a commercially available radioimmunoassay kit (REN-K). Noradrenaline was measured using the sensitive radioenzymatic assay of Henry et al (1975). ACE activity must be measured immediately after collection of blood as loss of the inhibitory effect of captopril occurs when stored, even at -20°C, leading to an underestimation of in vivo inhibition (Boomsma et al, 1981;Roulston et al, 1980).…”

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confidence: 99%

Prolonged converting enzyme inhibition following captopril in patients with renal insuffficiency [letter]

Campbell¹,

Shepherd²,

Elliott³

et al. 1982

Brit J Clinical Pharma

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A sensitive radioenzymatic assay for norepinephrine in tissues and plasma

Cited by 479 publications

References 8 publications

Failure of plasma norepinephrine to consistently reflect sympathetic activity in humans.

Failure of plasma norepinephrine to consistently reflect sympathetic activity in humans.

An approach to the evaluation of genetic influences on factors that regulate arterial blood pressure in man.

Prolonged converting enzyme inhibition following captopril in patients with renal insuffficiency [letter]

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