Regulation of Substrate Oxidation in Isolated Myocardial Cells by β-Hydroxybutyrate

Summary

The role of ketone bodies in myocardial substrate oxidation was examined using freshly isolated Ca²⁺-tolerant heart myocytes, β-hydroxybutyrate (βOHB) inhibited lactate oxidation by the myocytes by 30-60%, and the inhibition was concentration dependent. Palmitate oxidation was also markedly decreased, whereas octanoate oxidation was only minimally affected by the presence of βOHB. Lactate, octanoate, or palmitate had little, if any, effect on βOHB oxidation. βOHB oxidation was reduced by 22-28% in myocytes isolated from chronically diabetic rats, whereas the oxidation of palmitate remained similar to the controls. However, βOHB still inhibited palmitate oxidation to the same extent as in the control cells. Our data support the role of βOHB as a physiologic regulator of myocardial substrate metabolism.

Key-Words:

Metabolism - Myocardium - β-Hydroxybutyrate - Glucose - Lactate - Palmitate - Diabetes Mellitus