Myocardial effects and pharmacokinetics of digoxin and ouabain in protein-deficient guinea pigs.

Myocardial effects and pharmacokinetics of digoxin and ouabain were studied in male albino guinea pigs fed ad libitum either a 21% (control) or a 5% (low) protein diet for 4 weeks. Dietary protein deficiency was associated with a decrease in body weight gain, ventricular weight, total plasma proteins and plasma albumin, hepatic total and microsomal proteins, cytochrome P-450, and protein:DNA ratios; serum potassium was slightly but insignificantly decreased. No significant differences were found in the following experiments with digoxin and ouabain in control and protein-deficient animals: inotropic effects of ouabain on isolated papillary muscles and left atria; uptake of [3H]ouabain by isolated papillary muscles; ventricular fibrillatory doses of digoxin and ouabain in anesthetized animals and the concentrations of digoxin in plasma and papillary muscles at the onset of ventricular fibrillation in these animals; plasma half-life of digoxin in unanesthetized guinea pigs. It is concluded that although dietary protein deficiency influences several physiological and biochemical parameters it does not alter the myocardial effects and pharmacokinetics of digoxin and ouabain in guinea pigs.