13C MRS Shows Altered Cerebral Glucose Metabolism During Acute Mild Hypoglycemia in Humans

Kim van de Ven¹, Marinette van der Graaf¹, Bastiaan de Galan², Cees Tack², Arend Heerschap¹

Cerebral glucose metabolism was assessed by 13C-MRS under euglycemic (5.16 mmol/l) or hypoglycemic (2.95 mmol/l) conditions in 8 human volunteers during 2-hour hyperinsulinemic glucose clamps. Using 13C-1-glucose 20% solutions a stable plasma glucose 13C-enrichment was achieved, resulting in high SNR spectra. MRS-measurements were conducted with a 13C/1H volume head coil, and an ISIS-DEPT pulse sequence at 3T. Under hypoglycemic conditions, 13C signals of Asp3 and Glu2 reached a higher level, while Asp2 and Glu3 (and also Glu4) reached a lower level compared to euglycemic conditions This indicates altered cerebral glucose metabolism during mild hypoglycemia, possibly reflecting upregulated anaplerosis.