RT Journal Article
T1 Effects of glucose and insulin on glucokinase activity in rat hypothalamus
A1 Sanz Miguel, María Del Carmen
A1 Roncero Rincón, Isabel
A1 Vázquez Pérez, Patricia
A1 Navas Hernández, María Ángeles
A1 Blázquez Fernández, Enrique
AB In an attempt to study the role of glucokinase (GK) and the effects of glucose and peptides on GK gene expression and on the activity of this enzyme in the hypothalamus, we used two kinds of biological models: hypothalamic GT1-7 cells and rat hypothalamic slices. The expression of the GK gene in GT1-7 cells was reduced by insulin (INS) and was not modified by different glucose concentrations, while GK enzyme activities were significantly reduced by the different peptides. Interestingly, a distinctive pattern of GK activities between the ventromedial hypothalamus (VMH) and lateral hypothalamus (LH) were found, with higher enzyme activities in the VMH as the glucose concentrations rose, while LH enzyme activities decreased at 2.8 and 20 mM glucose, the latter effect being prevented by incubation with INS. These effects were produced only by d-glucose and the modifications found were due to GK, but not to other hexokinases. In addition, GK activities in the VMH and the LH were reduced by glucagon-like peptide 1, leptin, orexin B, INS, and neuropeptide Y (NPY), but this effect was only statistically significant for NPY in LH. Our results indicate that the effects of both glucose and peptides occur on GK enzyme activities rather than on GK gene transcription. Moreover, the effects of glucose and INS on GK activity suggest that in the brain GK behaves in a manner opposite to that in the liver, which might facilitate its role in glucose sensing. Finally, hypothalamic slices seem to offer a good physiological model to discriminate the effects between different areas.
PB BioScientifica
SN 0022-0795
SN 1479-6805
YR 2007
FD 2007
LK https://hdl.handle.net/20.500.14352/96175
UL https://hdl.handle.net/20.500.14352/96175
LA eng
NO Sanz C, Roncero I, Vázquez P, Navas MA, Blázquez E. Effects of glucose and insulin on glucokinase activity in rat hypothalamus. J Endocrinol. 2007;193(2):259-267. doi:10.1677/JOE-06-0146
DS Docta Complutense
RD 20 jul 2024