FIGURE 1 The homeostatic pathway of energy balance
From the following article:
Childhood obesity: behavioral aberration or biochemical drive? Reinterpreting the First Law of Thermodynamics
Robert H Lustig
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Figure 1. The homeostatic pathway of energy balance
Afferent (blue), central (brown), and efferent (white) pathways are delineated. The hormones insulin, leptin, ghrelin, and peptide YY3–36 provide afferent information to the ventromedial hypothalamus, relating to short-term energy metabolism and energy sufficiency. From there, the ventromedial hypothalamus elicits anorexigenic (
-melanocyte stimulating hormone, cocaine-amphetamine regulated transcript) and orexigenic (neuropeptide Y, agouti-related protein) signals to the melanocortin 4 receptor in the paraventricular nucleus and lateral hypothalamic area. These signals lead to efferent output via the locus coeruleus and the nucleus tractus solitarius, which activates the sympathetic nervous system and causes adipocytes to undergo lipolysis, or via the dorsal motor nucleus of the vagus, which activates the vagus nerve and causes energy storage, both by increasing pancreatic insulin secretion, and (in rodents) by increasing adipose-tissue sensitivity to insulin.9 Reproduced with permission from reference 9 © (2001) Elsevier Inc. Abbreviations: 5-HT, serotonin (5-hydroxytryptamine); DMV, dorsal motor nucleus of the vagus; LC, locus coeruleus; LHA, lateral hypothalamic area; NE, norepinephrine; NTS, nucleus tractus solitarius; PVN, paraventricular nucleus; PYY3–36, peptide YY3–36; VMH, ventromedial hypothalamus.
