Purpose <p>Although glucagon-like peptide-1 (GLP-1), a hormone secreted by intestinal endocrine L cells, exerts cardioprotective effects against myocardial ischemia–reperfusion injury through protein kinase A (PKA) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathways, it remains unclear whether GLP-1 affects normal rat heart function by activating these signaling pathways.</p> Methods <p>Rats were randomly divided into eight groups (<i>n</i> = 6 per group): control, GLP-1 10^− 12 M, GLP-1 10^− 11 M, GLP-1 10^− 10 M, GLP-1 10^− 9 M, GLP-1 10^− 8 M, GLP-1 10^− 7 M, and GLP-1 10^− 6 M. Following a 20-min stabilization period with Krebs–Henseleit (KH) buffer in the Langendorff system, baseline hemodynamic parameters were recorded. The control group then received KH buffer for 30&#xa0;min. The GLP-1 groups received GLP-1 at their respective concentrations for 30&#xa0;min. At the end of the perfusion period, each heart was rapidly frozen for the assessment of PKA and phospho-protein kinase B/total-Akt in myocardial tissue using western blot analysis.</p> Results <p>No significant changes in protein expression or cardiac function were observed under physiological conditions.</p> Conclusion <p>Our results suggest that the action of GLP-1 on cardiac tissue may differ between ischemic and non-ischemic conditions.</p> Graphical Abstract <p></p>