Monocarboxylate transporter expression in mouse brain.
Although glucose is the major metabolic fuel needed for normal brain function, monocarboxylic acids, i.e., lactate, pyruvate, and ketone bodies, can also be utilized by the brain as alternative energy substrates. In most mammalian cells, these substrates are transported either into or out of the cell by a family of monocarboxylate transporters (MCTs), first cloned and sequenced in the hamster. We have recently cloned two MCT isoforms (MCT1 and MCT2) from a mouse kidney cDNA library. Northern blot analysis revealed that MCT1 mRNA is ubiquitous and can be detected in most tissues at a relatively constant level. MCT2 expression is more limited, with high levels of expression confined to testes, kidney, stomach, and liver and lower levels in lung, brain, and epididymal fat. Both MCT1 mRNA and MCT2 mRNA are detected in mouse brain using antisense riboprobes and in situ hybridization. MCT1 mRNA is found throughout the cortex, with higher levels of hybridization in hippocampus and cerebellum. MCT2 mRNA was detected in the same areas, but the pattern of expression was more specific. In addition, MCT1 mRNA, but not MCT2, is localized to the choroid plexus, ependyma, microvessels, and white matter structures such as the corpus callosum. These results suggest a differential expression of the two MCTs at the cellular level.
Koehler-Stec
E M
EM
Experimental Diabetes, Metabolism and Nutrition Section, Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Simpson
I A
IA
Vannucci
S J
SJ
Landschulz
K T
KT
Landschulz
W H
WH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D006224:Cricetinae; D004822:Epididymis / Q000378:metabolism; D015723:Gene Library; D017403:In Situ Hybridization; D007668:Kidney / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D027501:Monocarboxylic Acid Transporters; D009928:Organ Specificity; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000378:metabolism; D014158:Transcription, Genetic
D002352:Carrier Proteins; D027501:Monocarboxylic Acid Transporters; D012333:RNA, Messenger; D011994:Recombinant Proteins; C490426:Slc16a7 protein, mouse