Bivalent effects of human growth hormone in experimental myocardial infarcts. Protective when administered alone and aggravating when combined with beta blockers.

Treatment With Growth Hormone Enhances Contractile Reserve and Intracellular Calcium Transients in Myocytes From Rats With Postinfarction Heart Failure

“…49 The present study also did not address potential interactive effects of growth hormone therapy with ␤-adrenergic blockers, which now play an important role in the long-term treatment of patients after infarction. 19 With these limitations, the present study shows that growth hormone increases contractile reserve in myocytes of postinfarction rats and supports the hypothesis that growth hormone treatment has a direct effect on myocyte contractile function and intracellular calcium regulation. …”

“…17 Treatment with growth hormone early after experimental coronary ligation also preserved collagen matrix and reduced aneurysm formation, 18 although this favorable effect was not observed when growth hormone was administered together with ␤-adrenergic blockers. 19 The benefits of the induction of mild concentric hypertrophy early after experimental infarction with regard to retarding left ventricular dilatation and improving systolic function have also been clearly demonstrated by Litwin et al 20 in response to a different growth-promoting agent, 2-tetradecylglycidic acid.…”

Growth hormone alone or combined with metoprolol preserves cardiac function after myocardial infarction in rats

“…It has previously been reported that GH and atenolol in combination increases the frequency of aneurysms in rats after experimental MI [17]. When given alone GH prevented the formation of aneurysms [17,34].…”

“…However, introduction of GH into the therapeutic armamentarium of CHF needs to be explored since little is known about the possible interactions with GH and the sympathetic nervous system. An early report from Castagnini et al [17], showed a negative impact of the combined treatment with regard to the prevalence of LV aneurysms after MI in an experimental rat model.…”

Cardiac and peripheral actions of growth hormone and its releasing peptides: Relevance for the treatment of cardiomyopathies

“…Effect of GH/IGF-1 on post-myocardial infarction heart failure As shown in Table 1, initial studies investigating the effects of early GH treatment on ventricular remodelling post-MI in rats reported a reduction of ventricular aneurysms 25 days post-infarction, following a 3-day treatment with recombinant human GH (rhGH) (0.17 mg/kg daily) beginning the day of left coronary artery ligation (LCAL) [21]. The beneficial effects of GH were attributed to the preservation of the collagen network.…”