[Insulin as a humoral factor of energy supply for the biological function of locomotion].
From the point of view of general biology the author considers hyperglycemia and glucagon to have in the course of phylogenesis provided cells with a capability of in vivo glucose (GLU) uptake and depositing it in the form of glycogen. At the same time gluconeogenesis, facilitated GLU uptake via transporters and passive non-etherified fat acid (FA) uptake by myocytes were formed. Millions years later changes in dietary habits and motion initiated beta-cells and insulin system in order to provide energy for biological function of locomotion (migrations). Glucagon-regulated processes are not affected by insulin (INS). Myocytes became INS-independent cells; in cases of functional INS-resistance, which prevented them from depositing large amount of GLU, the hormone initiated lipogenesis i.e. conversion of GLU into saturated palmitic fat acid FA and its etherification into triglycerides. To deposit them INS initiated the differentiation of adipocytes (the second INS-independent cell). INS initiated the synthesis of apoE and active receptor uptake of FA by cells in the form of triglycerides through apoE/B- 100 receptor endocytosis. Since myocytes oxidize unsaturated FA more rapidly, INS initiated the system of elongases and desaturases and the conversion of saturated palmitic FA into unsaturated oleic FA in adipocytes. The contractile activity of myocytes is the main physiologic counter-regulator of INS. Within millions of years of phylogenesis INS had been forming the system of supplying myocytes with energy and perfecting the biological function of locomotion which Homo sapiens virtually lost in a moment.
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D000818:Animals; D004705:Endocytosis / Q000502:physiology; D005934:Glucagon / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008124:Locomotion / Q000502:physiology*; D051379:Mice; D032342:Muscle Cells / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology
D007328:Insulin; D005934:Glucagon; D005947:Glucose