Short-term food restriction and refeeding alter expression of genes likely involved in brain glucosensing.
Several genes involved in glucosensing of the endocrine pancreas have been proposed to serve a similar function in the brain. These genes include the glucose transporter-2 (Glut-2) and glucokinase (GK). In addition, the glucagon-like peptide 1 receptor, which serves as a downstream signal modulator in pancreatic glucosensing and centrally alters feeding, is also of interest. We used quantitative real-time RT-PCR to measure changes in hypothalamic and brainstem Glut-2, GK, and Glp-1R expression of these genes induced by food restriction and refeeding. Sprague-Dawley rats were 50% food restricted for 1 day; one-half of the food-restricted rats were refed with chow for 1 hr before sacrifice. In both hypothalamus and brainstem, gene expression of Glut-2, GK, and Glp-1R was significantly lower in refed rats compared with food-restricted rats. The measures of gene expression in two feeding control groups (ad libitum and voluntarily overfed animals) were intermediate between the food-restricted and refed groups, but were not significantly different from each other. The results indicate that putative glucosensing (GK, Glut-2, and Glp-1R) gene expression in the hypothalamus and brainstem is reduced in response to food intake, depending on prior nutritional status.
Zhou
Jun
J
Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana 70808, USA. Zhouj@pbrc.edu
Roane
David S
DS
Xi
Xiaochun
X
Bogacka
Iwona
I
Li
Bing
B
Ryan
Donna H
DH
Martin
Roy J
RJ
D000818:Animals; D001921:Brain / Q000378:metabolism*; D005508:Food Deprivation / Q000502:physiology*; D005786:Gene Expression Regulation; D000067757:Glucagon-Like Peptide-1 Receptor; D005941:Glucokinase / Q000235:genetics*; D005947:Glucose / Q000378:metabolism; D051273:Glucose Transporter Type 2; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018027:Receptors, Glucagon / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D051273:Glucose Transporter Type 2; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; D018027:Receptors, Glucagon; D005941:Glucokinase; D005947:Glucose