High sodium diet and circulating digitalis-like compound in the rat.
The effects of a high salt diet (8% NaCl) on blood pressure and intra-erythrocytic Na+ content were studied in Wistar rats. The ability of the plasma to inhibit the renal Na+,K+-ATPase activity and to cross-react with digoxin antibodies was also investigated. After 1 week, neither systolic blood pressure nor intra-erythrocytic Na+ content were modified, but plasma extracts slightly inhibited renal Na+,K+-ATPase (70.9 +/- 1.7 versus 76.3 +/- 2.1 mumol Pi/mg per h, P = 0.05). After 2 weeks, the plasma inhibitory activity, systolic blood pressure and intra-erythrocytic Na+ content were higher than corresponding values in control animals (65.5 +/- 1.6 versus 79.1 +/- 2.8 mol Pi/mg per h, P less than 0.001; 132 +/- 2 versus 114 +/- 4 mmHg, P less than 0.001, and 4.95 +/- 0.32 versus 3.81 +/- 0.36 mmol/l cells, P less than 0.05, respectively). After 3 months, the plasma digoxin-like immunoreactivity and its ability to inhibit the Na+ pump were elevated (68.7 +/- 7.9 versus 48.2 +/- 5.4 pg/ml, P less than 0.02; 57.8 +/- 1.8 versus 72.9 +/- 1.8 mumol Pi/mg per h, P less than 0.001, respectively) whereas intra-erythrocytic Na+ content had returned to control levels. The results demonstrated that this high salt intake led to simultaneous increases in systolic blood pressure and in the activity of a digitalis-like compound present in plasma. The inhibition of Na+,K+-ATPase was correlated with systolic blood pressure and digoxin-like immunoreactivity (r = 0.569, n = 76, P less than 0.001 and r = 0.414, n = 34, P less than 0.02, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D001794:Blood Pressure; D001798:Blood Proteins / Q000378:metabolism*; D002298:Cardenolides; D004077:Digoxin; D004912:Erythrocytes / Q000378:metabolism; D006973:Hypertension / Q000209:etiology; D007473:Ion Channels / Q000378:metabolism; D007668:Kidney / Q000201:enzymology; D008055:Lipids / Q000097:blood; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012503:Saponins; D012964:Sodium / Q000008:administration & dosage* / Q000097:blood; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors; D013997:Time Factors
D001798:Blood Proteins; D002298:Cardenolides; D007473:Ion Channels; D008055:Lipids; D012503:Saponins; C034504:digoxin-like factors; D004077:Digoxin; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase