Brain Glucose in Steady-State During Hypoglycemia
(HealthDay News) – The plasma-to-brain glucose relationship and the calculations demonstrating glucose transport over the blood-brain barrier do not differ between healthy subjects and patients with uncomplicated, reasonably well-controlled type 1 diabetes mellitus (T1DM).
To examine the relationship between plasma and brain glucose levels during euglycemia and hypoglycemia, Kim CC van de Ven, from the Radboud University Nijmegen Medical Centre in the Netherlands, and colleagues used hyperinsulinemic, euglycemic, and hypoglycemic [1-13C]glucose clamps in eight healthy subjects and nine patients with uncomplicated T1DM (hemoglobin A1c, 7.7%±1.4%). Magnetic resonance spectroscopy was used to measure brain glucose levels.
The researchers observed comparable brain glucose values during euglycemia and hypoglycemia between healthy subjects and T1DM patients. The data from Michaelis-Menten (MM) kinetic parameters for maximum transport rate/cerebral metabolic rate of glucose and substrate concentration at half maximal transport were similar to previously published data obtained under hyperglycemic conditions.
"In conclusion, our data show that the linear MM relationship between plasma and brain glucose reported previously extends well into the hypoglycemic range in patients with T1DM and nondiabetic control subjects," the authors write. "Our data also show that brain glucose content and kinetics of brain glucose transport do not differ between healthy subjects and patients with uncomplicated T1DM under hypoglycemic conditions."