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
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Myocardium
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β-Hydroxybutyrate
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Glucose
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Lactate
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Palmitate
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Diabetes Mellitus
