Distribution of glucose transporter messenger RNA transcripts in tissues of rat and man

We used the complementary DNA for the human hepatoma Hep G2 glucose transporter to determine the distribution of glucose transporter messenger RNA (mRNA) in rat and human tissues. Under stringent hybridization conditions, a single 2.8-kilobase (kb) transcript is seen in all rat and human tissues examined. The mRNA is most abundant in brain, and is especially enriched in the brain microvascular fraction. The mRNA abundance in rat muscle and fat is 5% that in brain. Rat liver (both adult and fetal) and human liver have very little 2.8-kb mRNA, but it is abundant in cultured human fibroblasts and EB virus-transformed lymphoblasts. The same size mRNA is present in leg muscle of two type II diabetic patients. A very homologous glucose transporter mRNA is expressed in both insulin-sensitive and -insensitive tissues of rat and man. Hepatocytes, which have abundant glucose transport, may express a homologous but nonidentical glucose transporter.