Further studies on the cardiomegaly induced by beta-adrenoceptor agonists.
Rats received continuous infusions of beta-adrenoceptor agonists by means of Alzet osmotic minipumps implanted subcutaneously. After 7 days of isoprenaline infusion (2 mg/kg per day) the heart/body weight ratio increased about 40 per cent compared with placebo treatment. The difference persisted after freeze-drying indicating a true hypertrophy and not merely an oedema. When terbutaline (20 mg/kg per day) was substituted for isoprenaline, the increase in wet weight ratio reached only about 5 per cent. Procaterol (2 mg/kg per day) and pirbuterol (20 mg/kg per day) had no effect on the heart weight. It is concluded that in doses expected to cause comparable stimulation of beta 2-adrenoceptors the unselective agonist isoprenaline is able, more than the beta 2-selective agonists terbutaline, procaterol and pirbuterol to cause cardiac hypertrophy thus indicating the involvement of beta 1-adrenoceptors.
Jeppsson
A B
AB
Waldeck
B
B
Widmark
E
E
D000318:Adrenergic beta-Agonists; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D006332:Cardiomegaly / Q000139:chemically induced*; D004983:Ethanolamines / Q000494:pharmacology; D006168:Guinea Pigs; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D017265:Procaterol; D051381:Rats; D011919:Rats, Inbred Strains; D013726:Terbutaline / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D004983:Ethanolamines; D007545:Isoproterenol; D013726:Terbutaline; C009118:pirbuterol; D017265:Procaterol