Study of the factors influencing cardiac growth. III. Digitoxin treatment and thyroxine-induced cardiac hypertrophy in the rat.
Thyroxine (T4) administered to rats in a dose of 1 mg/kg for 12 days induces cardiac hypertrophy. The purpose of the present study was to determine the effect of prophylactic + simultaneous digitoxin treatments on the development of T4-induced cardiac hypertrophy. Digitoxin (1 mg/kg body weight) was given per os, once daily for 6 days prior to T4 administration and continued simultaneously with T4 treatment. To determine myocardial enlargement, wet heart weight, myocardial nucleic acid and protein were measured. Digitoxin treatment induced a slight increase in wet ventricle weight and a significant elevation of myocardial RNA content (mg/ventricles) and concentration (mg/g). At the same time, the degree of T4-induced cardiac hypertrophy in digitoxin-treated and untreated animals was nearly the same. On the basis of these results it can be stated that--unlike the cardiac hypertrophy induced by pressure overload or hypoxia,--the T4-induced cardiac hypertrophy is not altered by digitoxin administration.
D000818:Animals; D001835:Body Weight; D006332:Cardiomegaly / Q000139:chemically induced / Q000517:prevention & control*; D004247:DNA / Q000032:analysis; D004074:Digitoxin / Q000627:therapeutic use*; D008297:Male; D009206:Myocardium / Q000032:analysis; D009929:Organ Size; D010101:Oxygen Consumption; D011506:Proteins / Q000032:analysis; D012313:RNA / Q000032:analysis; D051381:Rats; D013974:Thyroxine / Q000009:adverse effects*
D011506:Proteins; D012313:RNA; D004247:DNA; D004074:Digitoxin; D013974:Thyroxine