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Scientific article
Open access
English

The rate-limiting step for glucose transport into the hypothalamus is across the blood-hypothalamus interface

Published inJournal of neurochemistry, vol. 109 Suppl 1, p. 38-45
Publication date2009
Abstract

Specialized glucosensing neurons are present in the hypothalamus, some of which neighbor the median eminence, where the blood-brain barrier has been reported leaky. A leaky blood-brain barrier implies high tissue glucose levels and obviates a role for endothelial glucose transporters in the control of hypothalamic glucose concentration, important in understanding the mechanisms of glucose sensing We therefore addressed the question of blood-brain barrier integrity at the hypothalamus for glucose transport by examining the brain tissue-to-plasma glucose ratio in the hypothalamus relative to other brain regions. We also examined glycogenolysis in hypothalamus because its occurrence is unlikely in the potential absence of a hypothalamus-blood interface. Across all regions the concentration of glucose was comparable at a given plasma glucose concentration and was a near linear function of plasma glucose. At steady-state, hypothalamic glucose concentration was similar to the extracellular hypothalamic glucose concentration reported by others. Hypothalamic glycogen fell at a rate of approximately 1.5 micromol/g/h and remained present in substantial amounts. We conclude for the hypothalamus, a putative primary site of brain glucose sensing that: the rate-limiting step for glucose transport into brain cells is at the blood-hypothalamus interface, and that glycogenolysis is consistent with a substantial blood -to- intracellular glucose concentration gradient.

Keywords
  • Algorithms
  • Animals
  • Biological Transport, Active/physiology
  • Blood Glucose/metabolism
  • Blood-Brain Barrier/physiology
  • Brain/anatomy & histology
  • Brain Chemistry/physiology
  • Glucose/metabolism
  • Glucose Transporter Type 1/metabolism
  • Glycogen/metabolism
  • Hypothalamus/metabolism
  • Kinetics
  • Liver Glycogen/metabolism
  • Male
  • Microwaves
  • Rats
  • Rats, Sprague-Dawley
  • Reproducibility of Results
  • Tissue Fixation
Research group
Citation (ISO format)
POITRY-YAMATE, Carole, LEI, Hongxia, GRUETTER, Rolf. The rate-limiting step for glucose transport into the hypothalamus is across the blood-hypothalamus interface. In: Journal of neurochemistry, 2009, vol. 109 Suppl 1, p. 38–45. doi: 10.1111/j.1471-4159.2009.05934.x
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Article (Published version)
accessLevelPublic
Identifiers
ISSN of the journal0022-3042
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1454downloads

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