The balance of energy intake and expenditure in the body is maintained by
the complex physiological mechanisms that integrate neuronal activity in various
central nervous system structures with signals coming from the gastrointestinal system,
adipose tissue, endocrine glands, and the autonomic nervous system. The arcuate
nucleus (ARC) in the ventral hypothalamus is considered to be the most important
integrational centre in the hypothalamus. Very porous hematoencephalic barrier around
arcuate nuclei allows numerous hormones, nutrients and cytokines from the periphery
to reach the nuclei and inform ARC of the amount of food consumed and energy stored
during the preceding hours, weeks, months and years. Information about short-term
fluctuations in the amount of food consumed is carried by hormones released from the
gastrointestinal tract (ghrelin, cholecystokinin, peptide YY, glucagon-like peptide) and
pancreas (insulin, amylin, pancreatic polypeptide), while information about the amount
of food consumed and energy stored during the preceding weeks or months is carried
by hormones released from adipose tissue (leptin and adiponectin). ARC, when
informed, secrete anorexigenic (alpha-melanocyte stimulating hormone) or orexigenic
neurotransmitters (neuropeptide Y, agouti-related protein, melanin-concentrating
hormone), which modulate the activity of second order hypothalamic nuclei such as the
paraventricular, ventromedial and dorsomedial nuclei, as well as the lateral
hypothalamus and thereby control eating behaviour and energy expenditure. In this
chapter, the interaction of peripheral hormones with anorexigenic/orexigenic neurons
and its effects on food intake are discussed.
Keywords: Adipokines, Anorexogenic, Arcuate nucleus, Gastrointestinal
hormones, Neuropeptides, Orexigenic, Pancreatic hormones.
