Hypothalamic actions of apelin on energy metabolism: new insight on glucose homeostasis and metabolic disorders.
Hypothalamus is key area implicated in control of glucose homeostasis. This structure integrates nervous and peripheral informations to adapt a response modifying peripheral glucose utilization and maintaining energetic balance. Among peripheral signals, adipokines such as adiponectin and leptin are of special importance since deregulations of their actions are closely associated to metabolic disorders such as obesity and type 2 diabetes. During the past ten years, we have identified a new adipokine named apelin which has emerging role in the control of metabolism. The originality of the apelinergic system is to be largely represented in peripheral tissues (adipose tissue, intestine, etc.) and in the brain. Then, apelin is released by adipose tissue as all adipokines, but also present another crucial role as neurotransmitter in hypothalamic neurons. By acting in the whole body, apelin exerts pleiotropic actions and is now considered as a major determinant of physiological functions. Besides its general beneficial effects on peripheral targets, central action of apelin remains still a matter of debate. In this review, we have made a parallel between peripheral vs. central actions of apelin in term of signalization and effects. Then, we have focused our attention on hypothalamic apelin and its potential role in glucose metabolism and associated pathologies.
Institut National de la Santé et de la Recherche Médicale (INSERM), Toulouse, France.
C
C
Knauf
Institut National de la Santé et de la Recherche Médicale (INSERM), Toulouse, France.
A
A
Drougard
Institut National de la Santé et de la Recherche Médicale (INSERM), Toulouse, France.
A
A
Fournel
Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université catholique de Louvain, LDRI, Brussels, Belgium.
T
T
Duparc
Institut National de la Santé et de la Recherche Médicale (INSERM), Toulouse, France.
P
P
Valet
D000818:Animals; D000073861:Apelin; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism* / Q000473:pathology; D004734:Energy Metabolism; D005947:Glucose / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D007031:Hypothalamus / Q000378:metabolism* / Q000473:pathology; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism* / Q000473:pathology
C115436:APLN protein, human; D000073861:Apelin; D036341:Intercellular Signaling Peptides and Proteins; D005947:Glucose