The Hepato-portal Sensor

The effect is a nerve-mediated increased insulin secretion, particularly increased first phase activity [41-43], but the effect on glucose uptake is more pronounced. It appears that the neural response can increase the translocation of GLUT4 much like the effect of exercise and without concomitant changes in insulin concentration [44]. 

The features of the hepato-portal system together with the previous mentioned integral control supports the concept that the glucose-insulin control system is not so much a control of plasma glucose concentration as a system that controls the nutrient fluxes after a meal. 

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Especially at the beginning it is important that the nervous system is able to sense the meal and start the GEUT4 translocation. Here the activity of the hepato-portal sensor is ideal, because it gives a signal that is precisely proportional to Jabs. It is typically seen that the plasma insulin concentration increases before any noticeable increase in glucose concentration [121],... 

Tanaka K, Inoue S, Nagase H, Takamura Y, Niijima A. 1990. Amino acid sensors sensitive to alanine and leucine exist in the hepato-portal system in the rat. J Auton Nerv Syst 31 41-46. 

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