Farmasevtika instituti farmakologiya va klinik farmatsiya kafedrasi

Adenosine Triphosphate Is the ―Energy Currency‖ of the Body
Adenosine triphosphate (ATP) is an essential link between energy-utilizing and energy-producing 
functions of thebody (Figure 67-1). For this reason, ATP has been called the energy currency of the 
body, and it can be gained and spent repeatedly. Energy derived from the oxidation of carbohydrates, 
proteins, and fats is used to convert adenosine diphosphate (ADP) to ATP, which is then consumed by 
the various reactions of the body that are necessary for (1) active transport of molecules across cell 
membranes; (2) contraction of muscles and performance of mechanical work; (3) various synthetic 
reactions that create hormones, cell membranes, andmany other essential molecules of the body; (4) 
conduction of nerve impulses; (5) cell division and growth; and (6) many other physiologic functions 
that are necessary to maintain and propagate life. ATP is a labile chemical compound that is present in 
all cells 
Central Role of Glucose in Carbohydrate Metabolism 

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As explained in Chapter 65, the final products of carbohydrate digestion in the alimentary tract are 
almost entirely glucose, fructose, and galactose—with glucose representing, on average, about 80 
percent of these. After absorption from the intestinal tract, much of the fructose and almost all the 
galactose are rapidly converted into glucose in the liver. Therefore, little fructose and galactose are 
present in the circulating blood. 
Glucose thus becomes the final common pathway for the transport of 
almost all carbohydrates to the tissue cells
. In liver cells, appropriate enzymes are available to 
promote interconversions among the monosaccharides—glucose, fructose, and galactose—as shown in 
Figure 67-3. Furthermore, the dynamics of the reactions are such that when the liver releases the 
monosaccharides back into the blood, the final product is almost entirely glucose.