Sodium-lithium exchange and sodium-potassium cotransport in human erythrocytes. Part 2: A simple uptake test applied to normotensive and essential hypertensive individuals.

Duhm, Jochen; Göbel, B. O.; Lorenz, Rebecca; Pc, Weber

doi:10.1161/01.hyp.4.4.477

Cited by 88 publications

(27 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Interindividual variability in the measurements of Km and V, , , of the NaK cotransport system was much greater than those of NaK pump activity, consistent with the observations in studies of larger populations (22)(23)(24). Although the Co V, , , for Rb was slightly lower and the Km was slightly higher in CF RBC (Table I), these differences were not statistically significant.…”

Section: Resultssupporting

confidence: 85%

Kinetic Parameters of Rubidium Transport Pathways Are Normal in Cystic Fibrosis Red Cells

Joiner

1988

Pediatr Res

View full text Add to dashboard Cite

ABSTRACT. The abnormalities in ion transport in cystic fibrosis (CF) respiratory and sweat duct epithelia have prompted Studies of ion permeability in CF red blood cells (RBC) although previous reports have been contradictory. In this study, the kinetic characteristics of the three major cation transport systems in RBC were evaluated by measuring rubidium (Rb) uptake at various external Rb concentrations. The maximal velocity and affinity for external Rb (KH) of the NaK pump were normal in CF RBC, as were the maximal velocity and K, for Rb of the NaK cotransport system. Residual (ouabain and bumetanide insensitive) Rb uptake, and steady state RBC Na and K contents were also normal. These data indicate the NaK pump and cotransport system do not exhibit primary or secondary perturbations in CF RBC, and suggest that the noncarrier-mediated membrane permeability to cations is also normal in these cells. (Pediatr Res 24: 495-498, 1988) Abbreviations CF, cystic fibrosis RBC, red blood cell V , , maximal velocity K, Rb, external K or Rb PBS, phosphate-buffered saline OS, ouabain-sensitive Co, cotransport CF is an autosomal recessive disorder manifesting multiple exocrine abnormalities (1). The diagnostically important elevation of sweat chloride reflects malfunctioning of the salt resorbing mechanisms of sweat duct epithelium. Recent work has indicated that the basis of this dysfunction is low C1 permeability of the apical membrane of the ductal epithelial cells (2). Respiratory epithelia share this defect (3), which appears in these cells to arise from abnormalities of the adrenergic regulatory mechanisms of the C1 channel (4-6). Other recent studies of CF respiratory epithelia have also shown increased permeability of the apical membrane to Na, accompanied by elevated Na pump rates at the basolateral membrane, with increased numbers of [3H]ouabain binding sites and ouabain-inhibitable oxygen consumption (7). These findings suggest that, in addition to the C1 channel,

show abstract

Section: Resultssupporting

confidence: 85%

Kinetic Parameters of Rubidium Transport Pathways Are Normal in Cystic Fibrosis Red Cells

Joiner

1988

Pediatr Res

View full text Add to dashboard Cite

show abstract

“…The population described by Duhm et al 9 may represent another group in which the countertransport-blood pressure relationship is disordered.…”

Section: Discussionmentioning

confidence: 99%

Racial differences in erythrocyte cation transport.

Weder¹,

Torretti²,

Julius³

1984

Hypertension

101

View full text Add to dashboard Cite

SUMMARY Erythrocyte contents and ouabain-insensitive transport pathways were measured hi 120 white and black normotensives and hypertensives. Mean maximal sodium-stimulated lithiumsodium countertransport rate was higher in white hypertensives than in white normotensives, and countertransport was significantly positively correlated with mean arterial pressure in whites. Values similar to those in white normotensives were found in both black normotensives and hypertensives, and countertransport was not significantly correlated with blood pressure in blacks. The rate constant for passive lithium efflux was greater in whites as compared to blacks, and the difference was not related to blood pressure level or sex. Ouabain-insensitive, furosemide-sensitive sodium and potassium effluxes were not found to be altered in hypertension. Furosemide-sensitive sodium efflux rate was lower in blacks but furosemide-sensitive potassium efflux was not similarly depressed. While white subjects demonstrated a close correlation between sodium and potassium effluxes, blacks did not. Further study of these differences in the cellular metabolism of sodium and potassium may provide clues to the pathogenesis of racial dissimilarities in total body sodium handling. (Hypertension 6: 115-123, 1984) KEY WORDS • race • countertransport • cotransport • erythrocyte E RYTHROCYTE lithium-sodium countertransport and sodium-potassium cotransport have been proposed as markers for human essential hypertension. 1 2 Virtually all reports have included only white subjects. For lithium-sodium countertransport, Canessa and colleagues' 3 have consistently demonstrated enhanced maximal activity in white hypertensives and others 4 "* have confirmed the observation, although agreement is not universal. 9 Canessa et al.'°r eported that black hypertensives had values similar to those of black normotensives. Etkin et al." observed increases in tracer sodium influx rates in the erythrocytes of white essential hypertensives but not in blacks and suggested that tracer influx rate is closely correlated with the acitivity of the lithium-sodium countertransport system. 12 However, Trevisan et al. 13 found a significant correlation between lithium-sodium countertransport and blood pressure in black schoolchildren, and Woods et al. l4 found higher countertransport rates in blacks by comparing the normotensive sons of two hypertensive parents and the normotensive sons of normotensive parents.

show abstract

“…29 " 31 Contradictory findings have been reported and the relationships among various assays are unclear. "-2632 " 34 Rigorous sampling procedures that yield representative groups of participants have not always been applied and may have contributed to the lack of consistent results.…”

Section: Discussionmentioning

confidence: 99%

Abnormal red blood cell ion transport and hypertension. The People's Gas Company study.

Trevisan

Ostrow²,

Cooper³

et al. 1983

Hypertension

View full text Add to dashboard Cite

SUMMARY A population-based survey of 134 white men, recruited from the Chicago People's Gas Company labor force, was carried out to examine the association between sodium-lithium (Na-Li) countertransport and hypertension. Of the 134 participants in this industry-sponsored periodic health examination, 64 were normotensive and 70 were either taking antihypertensive medications or had a systolic pressure 3= 140 or a diastolic pressure 2= 90 mm Hg. The hypertensives were older and more overweight. Countertransport was significantly higher in hypertensives than in normotensives. Among the three subgroups of hypertensives -untreated borderline (140/90 to 160/95 mm Hg), untreated definite (over 160/95 mm Hg), and treated -an increase in countertransport was consistently observed, significant for the latter two groups. The relationship between countertransport and hypertension was independent of overweight, with countertransport being significantly related to both blood pressure and overweight. Altered ion transport may play an important role in the etiology and/or pathophysiology of hypertension. (Hypertension 5:363-367, 1983) KEY WORDS • countertransport • sodium metabolism • blood pressure R ED blood cell sodium-dependent membrane processes are currently being studied in relation to the etiology and pathogenesis of hypertension. 1 " 14 Previous case control studies have demonstrated a relationship between sodium-lithium (Na-Li) countertransport and hypertension.'-7 -15~17 This report described the results of a populationbased cross-sectional survey in employed white men relating levels of countertransport to the presence of hypertension. Methods Data CollectionVolunteers for this study were male employees (the great majority of whom were white) of the Chicago People's Gas Company participating in the companysponsored periodic health examination. The participation rate in this examination is over 90%. l8 During the period from June 1981 to December 1981, on a semi weekly basis, without selection the first four employees who presented at the company medical office for their regularly scheduled examination were invited to participate; response rate was 100%.A nurse measured blood pressure after the man had rested quietly in the sitting position for 5 minutes. Korotkoff sounds phases I and V were recorded from a single reading with a standard mercury sphygmomanometer. While blood was being sampled for routine laboratory analyses, an additional 15 cc of venous blood was collected in plastic tubes containing ammonium heparin. Samples were collected in the fasting state before 10 a.m. With the man in indoor clothes, with shoes off, height and weight were measured on a balance scale. Medical history was obtained through the use of a self-administered questionnaire.Of 157 white men participating in the study, 21 were excluded from this report because of a major illness (renal, hormonal, psychiatric) thought to influence intracellular ion metabolism. 6 l9 -2I In addition, two participants were excluded because of extremely...

show abstract

Sodium-lithium exchange and sodium-potassium cotransport in human erythrocytes. Part 2: A simple uptake test applied to normotensive and essential hypertensive individuals.

Cited by 88 publications

References 0 publications

Kinetic Parameters of Rubidium Transport Pathways Are Normal in Cystic Fibrosis Red Cells

Kinetic Parameters of Rubidium Transport Pathways Are Normal in Cystic Fibrosis Red Cells

Racial differences in erythrocyte cation transport.

Abnormal red blood cell ion transport and hypertension. The People's Gas Company study.

Contact Info

Product

Resources

About