Sweet and Low: Measuring Brain Glucose During Hypoglycemia
- 1Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
- 2Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota
- Corresponding author: Elizabeth R. Seaquist, .
In insulin-treated diabetes, the brain is exposed to extremes in glycemia that may have important effects on cerebral function. Consequently, understanding how the brain handles glucose delivered via the circulation under a range of glucose concentrations is important to patients with diabetes. In this issue of Diabetes, van de Ven et al. (1) report a new method to measure the kinetics of glucose transport under hypoglycemic conditions in human subjects. Their observations, coupled with the findings of others (2–4) provide firm evidence that a linear relationship exists between brain and blood glucose concentrations across the entire spectrum of glucose concentrations experienced by humans with uncomplicated type 1 diabetes. As a result, the brain is exposed to the same relative change in glucose concentration as the rest of the body during acute episodes of hypo- and hyperglycemia.
In the brain, glucose is transported across the blood-brain barrier by facilitated diffusion using GLUT1 (5). Once in the brain, glucose enters neurons via GLUT3 or astrocytes via GLUT1 (Fig. …