Body fluid variations and endogenous digitalis-like compounds during chronic NaCl loading in Wistar rats.
Circulating digitalis-like compounds have been proposed to be raised in volume expanded hypertension and to participate in Na+ homeostasis. We have investigated the temporal relationships between the activity of these circulating digitalis-like compounds, blood pressure and body fluid volume variations during a chronic NaCl load in the Wistar rat. Characteristics of salt-loaded rats were compared to those of weight-matched controls. At one week, when extracellular fluid volume (ECFV) was elevated, the capacity of plasma extracts to inhibit the Na+K+ATPase activity begun to rise. At two weeks, ECFV remained elevated, and plasma volume, blood pressure and the activity of plasma digitalis-like compounds increased. After 13 weeks, the continuous rise in plasma digitalis-like activity and in blood pressure was accompanied by the return of body fluid volumes towards control values. These changes in plasma digitalis-like activity, body fluid volumes, and systolic blood pressure during a high NaCl diet are compatible with the proposed role of circulating digitalis-like compounds as natriuretic and hypertensive factors.
Wauquier
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Department of Pharmacology, INSERM U7, CNRS UA 318, Necker Hospital, Paris, France.
Devynck
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MA
D000818:Animals; D001794:Blood Pressure; D001798:Blood Proteins / Q000502:physiology*; D001826:Body Fluids / Q000502:physiology*; D002298:Cardenolides; D004032:Diet; D004077:Digoxin; D004912:Erythrocytes / Q000378:metabolism; D008297:Male; D009318:Natriuresis; D051381:Rats; D011919:Rats, Inbred Strains; D012503:Saponins; D012964:Sodium / Q000097:blood; D012965:Sodium Chloride / Q000008:administration & dosage*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors
D001798:Blood Proteins; D002298:Cardenolides; D012503:Saponins; C034504:digoxin-like factors; D012965:Sodium Chloride; D004077:Digoxin; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase