Women with diabetes are up to five times more likely than the general population to have a baby with birth defects, especially of the heart and spinal cord, organs that form within the first few weeks of pregnancy.
In a mouse study published in the March 2007 Diabetologia, Joslin investigator Dr. Loeken and colleagues report that that a protein called glucose transporter 2 (Glut2) carries high amounts of glucose to the embryo’s cells when the mother’s blood glucose concentrations are high. This makes the embryo very susceptible to the malformations that high glucose levels cause.
Glut2 works efficiently only when glucose levels are high. In a normal pregnancy, the glucose in the mother’s blood that circulates to the uterus is never high enough to activate Glut2, so the embryo is not exposed to high concentrations of glucose. But glucose concentrations can be very high during a diabetic pregnancy. This activates Glut2, which carries these glucose levels to the embryo cells. The cells then act like a sponge, absorbing glucose at a much higher rate than normal.
Recent research has shown that Glut2 is also a transporter for glucosamine, an amino sugar that serves important functions in the synthesis of proteins. Since glucosamine is synthesized in the liver, which the early embryo lacks, it must get it from the mother’s circulation. Thus, Glut2 could required by the embryo for glucosamine transport, with the unfortunate side effect it has on glucose.
Medical News Today