A Case of Mistaken Identity

Abstract

The following is the abstract of the article discussed in the subsequent letter:Lavrentyev EN, He D, and Cook GA. Expression of several genes participating in regulation of fatty acid and glucose utilization and energy metabolism in the rat heart during development. The heart is a unique organ that can use several fuels for energy production. During development, the heart undergoes changes in fuel supply, and it must be able to respond to these changes. We have examined changes in the expression of several genes that regulate fuel transport and metabolism in rat hearts during early development. At birth, there was increased expression of fatty acid transporters and enzymes of fatty acid metabolism that allow fatty acids to become the major source of energy for cardiac muscle during the first 2 wk of life. At the same time, expression of genes that control glucose transport and oxidation was downregulated. After 2 wk, expression of genes for glucose uptake and oxidation was increased, and expression of genes for fatty acid uptake and utilization was decreased. Expression of carnitine palmitoyltransferase I (CPT I) isoforms during development was different from published data obtained from rabbit hearts. CPT I␣ and I␤ isoforms were both highly expressed in hearts before birth, and both increased further at birth. Only after the second week did CPT I␣ expression decrease appreciably below the level of CPT I␤ expression. These results represent another example of different expression patterns of CPT I isoforms among various mammalian species. In rats, changes in gene expression followed nutrient availability during development and may render cardiac fatty acid oxidation less sensitive to factors that influence malonyl-CoA content (e.g., fluctuations in glucose concentration) and thereby favor fatty acid oxidation as an energy source for cardiomyocytes in early development. A Case of Mistaken IdentityTo the Editor: I read the article "Expression of several genes participating in regulation of fatty acid and glucose utilization and energy metabolism in the rat heart during development" by Lavrentyev et al. (1) with great interest. The authors describe the developmental regulation of several genes, including fatty acid transports, involved in cardiac lipid metabolism using cDNAs from rat hearts and real-time PCR. One of the rat genes, which regulation is discussed in more detail, has GenBank accession no. D85100 and is identified by the authors as the rat ortholog of human and mouse fatty acid transport protein (FATP)6.My group has been working with the FATP gene family for several years, and I was surprised by the Cook's group finding that "It appears that FATP6 may function mostly during the fetal and early newborn period rather than in the adult," because we clearly demonstrated (2) expression of this protein in the adult mouse heart. So I took the liberty of aligning rat protein D85100 with their mouse and human counterparts using the ClustalW algorithm (3).To my astonishment, I found that D85100 is most homologous ...

Synthesis and preliminary evaluation of an 18 F-labeled oleic acid analog for PET imaging of fatty acid uptake and metabolism

“…FATP6 is highly expressed in the mouse myocardial tissue compared to low expression of FATP1 [30]. However, in rat heart, FATP1 is expressed at higher levels than FATP6 [31]. The incorporation of fluorine and sulfur atoms, while being reasonable isoteres of…”