Sweet and Low: Measuring Brain Glucose During Hypoglycemia

  1. Gülin Öz2
  1. 1Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
  2. 2Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota
  1. Corresponding author: Elizabeth R. Seaquist, seaqu001{at}umn.edu.

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 (24) 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. …

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