Thyroxine influences on contractile proteins from atrial and ventricular myocardium.
When thyroxine is administered to rats or rabbits, both heart ventricles eventually undergo hypertrophy. Both atria and ventricles show a relative weight increase and this mainly involves sarcoplasmic proteins. Ventricular myosin from thyrotoxic rabbits has higher Ca2+-ATPase activity when compared with euthyroid rabbits, the hyperthropied atria however, show no change in myosin ATPase after thyroxine administration.
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D006332:Cardiomegaly / Q000139:chemically induced; D003285:Contractile Proteins / Q000032:analysis*; D006321:Heart / Q000187:drug effects*; D006325:Heart Atria / Q000187:drug effects; D006352:Heart Ventricles / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000032:analysis; D009218:Myosins / Q000032:analysis; D009929:Organ Size; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D013974:Thyroxine / Q000494:pharmacology*
D003285:Contractile Proteins; D009218:Myosins; D000252:Calcium-Transporting ATPases; D013974:Thyroxine