Localization of glucokinase-like immunoreactivity in the rat lower brain stem: for possible location of brain glucose-sensing mechanisms

Endocrinology. 2000 Jan;141(1):375-84. doi: 10.1210/endo.141.1.7234.


Pancreatic glucokinase (GK) is considered an important element of the glucose-sensing unit in pancreatic beta-cells. It is possible that the brain uses similar glucose-sensing units, and we employed GK immunohistochemistry and confocal microscopy to examine the anatomical distribution of GK-like immunoreactivities in the rat brain. We found strong GK-like immunoreactivities in the ependymocytes, endothelial cells, and many serotonergic neurons. In the ependymocytes, the GK-like immunoreactivity was located in the cytoplasmic area, but not in the nucleus. The GK-positive ependymocytes were found to have glucose transporter-2 (GLUT2)-like immunoreactivities on the cilia. In addition, the ependymocytes had GLUT1-like immunoreactivity on the cilia and GLUT4-like immunoreactivity densely in the cytoplasmic area and slightly in the plasma membrane. In serotonergic neurons, GK-like immunoreactivity was found in the cytoplasm and their processes. The present results raise the possibility that these GK-like immunopositive cells comprise a part of a vast glucose-sensing mechanism in the brain.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antibody Specificity
  • Brain Stem / enzymology*
  • Ependyma / cytology
  • Ependyma / metabolism
  • Female
  • Glucokinase / immunology
  • Glucokinase / metabolism*
  • Glucose / metabolism*
  • Immunohistochemistry
  • Lateral Ventricles / metabolism
  • Microscopy, Confocal
  • Raphe Nuclei / cytology
  • Raphe Nuclei / metabolism
  • Rats
  • Rats, Wistar
  • Serotonin / metabolism
  • Solitary Nucleus / enzymology
  • Subcellular Fractions / enzymology
  • Tissue Fixation


  • Serotonin
  • Glucokinase
  • Glucose