GLUT8 Is a Glucose Transporter Responsible for Insulin-Stimulated Glucose Uptake in the Blastocyst

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 97; no. 13; pp. 7313 - 7318
• Main Authors: Carayannopoulos, Mary O., Maggie M.-Y. Chi, Cui, Ying, Pingsterhaus, Joyce M., McKnight, Robert A., Mueckler, Mike, Devaskar, Sherin U., Moley, Kelle H.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 20.06.2000; National Acad Sciences; The National Academy of Sciences
• Subjects: Amino Acid Sequence; Animals; Biological Sciences; Biological Transport; Blastocyst; Blastocyst - metabolism; Cell lines; Cell membranes; Complementary DNA; Embryos; Gene Expression Regulation; Glucose - metabolism; Glucose Transport Proteins, Facilitative; Hypoglycemic Agents - pharmacology; Insulin; Insulin - pharmacology; Mice; Mice, Inbred BALB C; Molecular Sequence Data; Monosaccharide Transport Proteins - genetics; Monosaccharide Transport Proteins - metabolism; Oocytes; Proteins; Receptors; RNA; Sequence Analysis, Protein
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.97.13.7313

Mammalian preimplantation blastocysts exhibit insulin-stimulated glucose uptake despite the absence of the only known insulin-regulated transporter, GLUT4. We describe a previously unidentified member of the mammalian facilitative GLUT superfamily that exhibits ≈ 20-25% identity with other murine facilitative GLUTs. Insulin induces a change in the intracellular localization of this protein, which translates into increased glucose uptake into the blastocyst, a process that is inhibited by antisense oligoprobes. Presence of this transporter may be necessary for successful blastocyst development, fuel metabolism, and subsequent implantation. Moreover, the existence of an alternative transporter may explain examples in other tissues of insulin-regulated glucose transport in the absence of GLUT4.