Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/197826
Type: Artigo de periódico
Title: Citrate Diminishes Hypothalamic Acetyl-coa Carboxylase Phosphorylation And Modulates Satiety Signals And Hepatic Mechanisms Involved In Glucose Homeostasis In Rats.
Author: Cesquini, Maristela
Stoppa, Graziela R
Prada, Patrícia O
Torsoni, Adriana S
Romanatto, Talita
Souza, Alex
Saad, Mario J
Velloso, Licio A
Torsoni, Marcio A
Abstract: The hypothalamic AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) pathway is known to play an important role in the control of food intake and energy expenditure. Here, we hypothesize that citrate, an intermediate metabolite, activates hypothalamic ACC and is involved in the control of energy mobilization. Initially, we showed that ICV citrate injection decreased food intake and diminished weight gain significantly when compared to control and pair-fed group results. In addition, we showed that intracerebroventricular (ICV) injection of citrate diminished (80% of control) the phosphorylation of ACC, an important AMPK substrate. Furthermore, citrate treatment inhibited (75% of control) hypothalamic AMPK phosphorylation during fasting. In addition to its central effect, ICV citrate injection led to low blood glucose levels during glucose tolerance test (GTT) and high glucose uptake during hyperglycemic-euglycemic clamp. Accordingly, liver glycogen content was higher in animals given citrate (ICV) than in the control group (23.3+/-2.5 vs. 2.7+/-0.5 microg mL(-1) mg(-1), respectively). Interestingly, liver AMPK phosphorylation was reduced (80%) by the citrate treatment. The pharmacological blockade of beta3-adrenergic receptor (SR 59230A) blocked the effect of ICV citrate and citrate plus insulin on liver AMPK phosphorylation. Consistently with these results, rats treated with citrate (ICV) presented improved insulin signal transduction in liver, skeletal muscle, and epididymal fat pad. Similar results were obtained by hypothalamic administration of ARA-A, a competitive inhibitor of AMPK. Our results suggest that the citrate produced by mitochondria may modulate ACC phosphorylation in the hypothalamus, controlling food intake and coordinating a multiorgan network that controls glucose homeostasis and energy uptake through the adrenergic system.
Subject: Amp-activated Protein Kinases
Acetyl-coa Carboxylase
Animals
Body Weight
Citric Acid
Corticosterone
Feeding Behavior
Glucose
Glucose Tolerance Test
Glycogen
Homeostasis
Hypothalamus
Injections, Intraventricular
Insulin
Liver
Male
Multienzyme Complexes
Phosphorylation
Propanolamines
Protein-serine-threonine Kinases
Rats
Rats, Wistar
Satiety Response
Signal Transduction
Rights: fechado
Identifier DOI: 10.1016/j.lfs.2008.04.015
Address: http://www.ncbi.nlm.nih.gov/pubmed/18534630
Date Issue: 2008
Appears in Collections:Unicamp - Artigos e Outros Documentos

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