Transport and Metabolism of Fatty Acids in Cultured Heart Muscle Cells from Neonatal Rats
Cultured heart muscle cells from neonatal rats take up and metabolize palmitate bound to albumin at rates higher than those for transporting fatty acids into the cells. Most of the metabolized fatty acids are esterified. The non-metabolized fatty acids comprise less than 10% of the fatty acids taken up. 2 mM of Pent-4-enoate reduced rates of palmitate conversion to CO2. “Starved” cells, devoid of glucose, in the presence of the uncoupler DNP, utilize only 20% of the supplied fatty acids but do not accumulate free fatty acids. When synthesized de novo from acetate, non-esterified fatty acids comprise 1–3% of the total fatty acids inside the myocytes and 2–13% in the extracellular medium. Diglycerides are the other export products. More than 80% of the esterified fatty acids remain inside the cells.
Decreased rates of intracellular utilization of fatty acids did not cause accumulation of fatty acids even when synthesized de novo. A putative sarcolemmal carrier may become saturated at low concentrations at the external binding site and blocked by bound FFA, preventing influx of more FFA across the sarcolemma. Intracellular accumulation of triglycerides is also prevented in myocytes due to lipolysis and export of the products — diglycerides and FFA.
KeywordsEhrlich Ascites Tumor Cell Culture Heart Cell Intracellular Lipase Esterify Fatty Acid Deplete Medium
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