Red cell sodium in DOCA-salt hypertension: a Brattleboro study.
The alteration of red cell Na+ content (Na+i), its causes and the possible relationship to the development of DOCA-salt hypertension were studied in Brattleboro rats. A pronounced hypertension developed in heterozygous (non-DI) animals that synthesize vasopressin (VP) although no substantial Na+i elevation was observed in their erythrocytes. In contrast, Na+i rose progressively in red cells of homozygous VP-deficient (DI) rats in which only marginal increase of systolic blood pressure was found after six weeks of DOCA-salt regimen. DOCA-salt treatment of non-DI rats did not cause major alterations in ouabain-resistant (OR) net Na+ uptake or ouabain-sensitive (OS) net Na+ extrusion but moderately increased furosemide-sensitive (FS) Rb+ uptake. The same treatment of DI rats doubled Na+i by an increased OR net Na+ uptake (due to a major elevation in both Na(+)-K+ cotransport and Na+ leak). Consequently, OS net Na+ extrusion was augmented in red cells of these animals. This was accompanied by an about threefold elevated FS Rb+ uptake. It can be concluded that a) the alterations of OR and/or OS Na+ or K+ transport observed in erythrocytes of Brattleboro DI rats are not essential for the development of severe DOCA-salt hypertension, b) red cell ion transport abnormalities revealed in DOCA-salt treated DI rats might be rather ascribed to cell potassium depletion, and c) increased inward Na(+)-K+ cotransport and Na+ leak causes red cell Na+i elevation that stimulates Na(+)-K+ pump activity.
Talib
H K
HK
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Zicha
J
J
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D001794:Blood Pressure; D002034:Bumetanide / Q000494:pharmacology; D003900:Desoxycorticosterone; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005665:Furosemide / Q000494:pharmacology; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D006973:Hypertension / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology*; D066298:In Vitro Techniques; D007700:Kinetics; D009392:Nephrectomy; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D011910:Rats, Brattleboro; D012413:Rubidium / Q000097:blood; D012964:Sodium / Q000097:blood*; D012982:Sodium, Dietary
D006454:Hemoglobins; D012982:Sodium, Dietary; D002034:Bumetanide; D003900:Desoxycorticosterone; D010042:Ouabain; D005665:Furosemide; D012964:Sodium; D012413:Rubidium