Hormones, glycemia, regulation of food intake and obesity
Apart from insulin and glucagon which we have just seen, several hormones, the majority of recent discovery, are implicated in glycemia regulation and in appetite regulation and food intake and consequently obesity.
These hormones are secreted by adipose tissue, the digestive tract and in particular the hypothalamic neurons. The same hormone can be found in the digestive tract and in the brain. For didactic reasons, we classify these hormones according to their principal, adipocyte, digestive or neuronal origin.
The center of regulation of food intake is the hypothalamus which synthesizes its own hormones, receives information from the periphery in the form of metabolites like glucose, of hormones of digestive and adipocyte origins and in the form of nervous impulses by the vagal afferents (pneumogastric nerve). The hypothalamus is in addition connected to various parts of the brain and to the autonomic nervous system, in particular the sympathetic nerves.
We summarize the effects of these hormones which are numerous and various by underlining those which relate to food intake and by recalling that many results in the literature come from animal experiments whose extrapolation to human and particularly to patients must remain careful.
Simplified regimen of the regulation of appetite and glycemia
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