Growth hormone alone or combined with metoprolol preserves cardiac function after myocardial infarction in rats.
OBJECTIVE
Beta-adrenoreceptor blocking agents are important for the treatment of myocardial infarction (MI). Accumulating evidence also indicates that growth hormone (GH) improves cardiac function after MI in rats. We aimed to investigate the cardiovascular effects of combined treatment in an animal model of MI.


METHODS
MI was induced in rats by ligation of the left coronary artery. Three days after MI, animals were randomly assigned to one of four groups: controls (C) (n=19); GH (n=19) receiving s.c. 2 mg/kg per day rhGH; metoprolol (M) group (n=19) receiving 24 mg/kg per day and combined group (GHM) (n=20) treated with both GH (2 mg/kg per day s.c.) and M (24 mg/kg per day) for 9 days. Transthoracic echocardiography was performed before and after treatment.


RESULTS
Serum levels of insulin-like growth factor I were significantly elevated in the GH-group but not in the GHM group compared to controls. Left ventricular volumes, cardiac index, systolic blood pressure, were similar in all groups. Percent changes in ejection fraction compared to baseline were; GH (6.1+/-5.0%) and GHM (6.1+/-4.2%) vs. C (-12.5+/-3.0%), P<0.01, M (-7.3+/-4.2%). The occurrence of aneurysms was not significantly different between the various treatment regimes.


CONCLUSIONS
Treatment with growth hormone alone or in combination with metoprolol preserved left ventricular function after MI.
Bollano
E
E
Wallenberg Laboratory, Sahlgrenska University Hospital, SE-41345, Göteborg, Sweden. entela.bollano@wlab.wall.gu.se
Bergh
C H
CH
Kjellström
C
C
Omerovic
E
E
Kujacic
V
V
Caidahl
K
K
Bengtsson
B A
BA
Waagstein
F
F
Isgaard
J
J
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000783:Aneurysm / Q000150:complications / Q000188:drug therapy; D000818:Animals; D001835:Body Weight; D004359:Drug Therapy, Combination; D004452:Echocardiography; D013006:Growth Hormone / Q000627:therapeutic use*; D006321:Heart / Q000502:physiology*; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000187:drug effects; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use*; D008955:Models, Cardiovascular; D009203:Myocardial Infarction / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013318:Stroke Volume / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology
D000319:Adrenergic beta-Antagonists; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D008790:Metoprolol