The median eminence as the hypothalamic area involved in rapid transfer of glucose to the brain: functional and cellular mechanisms.
J Mol Med (Berl)
; 97(8): 1085-1097, 2019 08.
Article
em En
| MEDLINE
| ID: mdl-31129757
Our data proposes that glucose is transferred directly to the cerebrospinal fluid (CSF) of the hypothalamic ventricular cavity through a rapid "fast-track-type mechanism" that would efficiently stimulate the glucosensing areas. This mechanism would occur at the level of the median eminence (ME), a periventricular hypothalamic zone with no blood-brain barrier. This "fast-track" mechanism would involve specific glial cells of the ME known as ß2 tanycytes that could function as "inverted enterocytes," expressing low-affinity glucose transporters GLUT2 and GLUT6 in order to rapidly transfer glucose to the CSF. Due to the large size of tanycytes, the presence of a high concentration of mitochondria and the expression of low-affinity glucose transporters, it would be expected that these cells accumulate glucose in the endoplasmic reticulum (ER) by sequestering glucose-6-phosphate (G-6-P), in a similar way to that recently demonstrated in astrocytes. Glucose could diffuse through the cells by micrometric distances to be released in the apical region of ß2 tanycytes, towards the CSF. Through this mechanism, levels of glucose would increase inside the hypothalamus, stimulating glucosensing mechanisms quickly and efficiently. KEY MESSAGES: ⢠Glucose diffuses through the median eminence cells (ß2 tanycytes), towards the hypothalamic CSF. ⢠Glucose is transferred through a rapid "fast-track-type mechanism" via GLUT2 and GLUT6. ⢠Through this mechanism, hypothalamic glucose levels increase, stimulating glucosensing.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Barreira Hematoencefálica
/
Glucose
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Hipotálamo
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Mitocôndrias
Limite:
Animals
Idioma:
En
Revista:
J Mol Med (Berl)
Assunto da revista:
BIOLOGIA MOLECULAR
/
GENETICA MEDICA
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Chile
País de publicação:
Alemanha