test_moissonnage_selune
type: Agent

Astrocytes and hypothalamic glucose sensing : metabolic role and involvement of astroglial connexins
type: Dataset
contact point: Organization
  fn: CCSD
keyword: sdvmheplife-sciences-q-biohuman-health-and-pathology
keyword: hypothalamic-glucose-sensing
keyword: homeostasie-energetique
keyword: sdvsalife-sciences-q-bioagricultural-sciences
keyword: energy-homeostasis
keyword: monocarboxylate-transporters-mcts
keyword: transporteurs-aux-monocarboxylates-mcts
keyword: theses
keyword: connexins-30-et-43
keyword: infoeu-reposemanticsdoctoralthesis
keyword: astrocytes
keyword: detection-hypothalamique-du-glucose-et-du-lactate
keyword: connexines-30-et-43
landing page: https://theses.hal.science/tel-00935261
description: The hypothalamus plays a pivotal role in the nervous control of glucose homeostasis. This area contains gluco-sensitive neurons. Some of them detect increases in glucose levels and regulate glucose homeostasis by stimulating insulin secretion or inhibiting food intake. It is widely accepted that astrocytes are metabolically coupled to neurons. Lactate, resulting from the metabolism of glucose by astrocytes, is transported via the monocarboxylate transporters (MCTs). In addition, gap junctions (GJ), that form networks within astrocytes, are essential to transfer glucose from the bloodstream to the active neurons. These astroglial GJ mainly consist of connexins 43 and 30 (Cxs).The aims of my thesis are twofold: first, to show that an intracarotid lactate injection toward the brain, as for glucose, triggers insulin secretion and, second, to investigate the role of astroglial Cxs.Our results demonstrate that lactate and glucose sensing are altered in 48h hyperglycemic rats (accompanied by high blood lactate level). These alterations are not due to changes in protein expression of astroglial or neuronal MCTs in the hypothalamus. We then show that Cx43 is highly expressed in astrocytic end-feet enwraping blood vessels, in medio-basal hypothalamus (MBH) where many gluco-sensitive neurons are present. The Cx30 expression is more diffuse in this structure. We also show that the protein expression of astroglial Cxs varies very rapidly due to changes in metabolic status (fasting, refeeding and hyperglycemia). To evaluate the involvement of astroglial Cx43 (the major isoform) in the hypothalamic glucose sensing, we silenced its expression in the MBH in vivo by injecting specific siRNA. A 30% diminution in protein levels (after 72h) induced a decrease in food intake without changes in weight, blood glucose and insulin levels compared to vehicle treated animals. The central response to glucose is drastically inhibited in terms of insulin secretion in siCx43 animals. Similarly, an…
identifier: NNT: 2012DIJOS097
issued: 2026-05-07T07:08:32.856572
language: fr
modified: 2026-05-07T07:08:32.856577

Astrocytes and hypothalamic glucose sensing : metabolic role and involvement of astroglial connexins
type: Distribution
access URL: https://theses.hal.science/tel-00935261
format: HTML
issued: 2026-05-07T07:08:32.865019
modified: 2026-05-07T07:08:32.837354