Pathways

Stanozolol is a drug that is not metabolized by the human body as determined by current research and biotransformer analysis. Stanozolol passes through the liver and is then excreted from the body mainly through the kidney.

The cellulase enzyme system consists of cellobiohydrolase, endoglucanase, and beta-glucosidase and has been extensively studied with respect to its biosynthesis, properties, mode of action, application, and, most recently, secretion mechanisms. A knowledge of the factors governing the biosynthesis and secretion of these enzymes at the molecular level will be useful in maximizing enzyme productivity in extracellular fluid.

Amylase enzymes secreted in saliva by the parotid gland and in the small intestine play an important role in initiating starch digestion. The products of starch digestion are but not limited to maltotriose, maltose, limit dextrin, and glucose. The action of enterocytes of the small intestine microvilli further break down limit dextrins and disaccharides into monosaccharides: glucose, galactose, and fructose. Once released from starch or once ingested, sucrose can be degraded into beta-D-fructose and alpha-D-glucose via lysosomal alpha-glucosidase or sucrose-isomaltase. Beta-D-fructose can be converted to beta-D-fructose-6-phosphate by glucokinase and then to alpha-D-glucose-6-phosphate by the action of glucose phosphate isomerase. Phosphoglucomutase 1 can then act on alpha-D-glucose-6-phosphate (G6P) to generate alpha-D-glucose-1-phosphate. Alpha-D-glucose-1-phosphate (G6P) has several possible fates. It can enter into gluconeogenesis, glycolysis or the nucleotide sugar metabolism pathway. UDP-glucose pyrophosphorylase 2 can convert alpha-D-glucose-1-phosphate into UDP-glucose, which can then be converted to UDP-xylose or UDP-glucuronate and, eventually to glucuronate. UDP-glucose can also serve as a precursor to the synthesis of glycogen via glycogen synthase. Glycogen is an analogue of amylopectin (“plant starch”) and acts as a secondary short-term energy storage for animal cells. It’s formed primarily in liver and muscle tissues, but is also formed at secondary sites such as the central nervous system and the stomach. In both cases it exists as free granules in the cytosol. Glycogen is a crucial element of the glucose cycle as another enzyme, glycogen phosphorylase, cleaves off glycogen from the nonreducing ends of a chain to producer glucose-1-phosphate monomers. From there, the glucose-1-phosphate monomers have three possible fates: (1) enter the glycolysis pathway as glucose-6—phosphate (G6P) to generate energy, (2) enter the pentose phosphate pathway to produce NADPH and pentose sugar, or (3) enter the gluconeogenesis pathway by being dephosphorylated into glucose in liver or kidney tissues. To initiate the process of glycogen chain-lengthening, glycogenin is required because glycogen synthase can only add to existing chains. This action is subsequently followed by the action of glycogen synthase which catalyzes the formation of polymers of UDP-glucose connected by (α1→4) glycosidic bonds to form a glycogen chain. Importantly, amylo (α1→4) to (α1→6) transglycosylase catalyzes glycogen branch formation via the transfer of 6-7 glucose residues from a nonreducing end with greater than 11 residues to the C-6 OH- group in the interior of a glycogen molecule.

Amylase enzymes secreted in saliva by the parotid gland and in the small intestine play an important role in initiating starch digestion. The products of starch digestion are but not limited to maltotriose, maltose, limit dextrin, and glucose. The action of enterocytes of the small intestine microvilli further break down limit dextrins and disaccharides into monosaccharides: glucose, galactose, and fructose. Once released from starch or once ingested, sucrose can be degraded into beta-D-fructose and alpha-D-glucose via lysosomal alpha-glucosidase or sucrose-isomaltase. Beta-D-fructose can be converted to beta-D-fructose-6-phosphate by glucokinase and then to alpha-D-glucose-6-phosphate by the action of glucose phosphate isomerase. Phosphoglucomutase 1 can then act on alpha-D-glucose-6-phosphate (G6P) to generate alpha-D-glucose-1-phosphate. Alpha-D-glucose-1-phosphate (G6P) has several possible fates. It can enter into gluconeogenesis, glycolysis or the nucleotide sugar metabolism pathway. UDP-glucose pyrophosphorylase 2 can convert alpha-D-glucose-1-phosphate into UDP-glucose, which can then be converted to UDP-xylose or UDP-glucuronate and, eventually to glucuronate. UDP-glucose can also serve as a precursor to the synthesis of glycogen via glycogen synthase. Glycogen is an analogue of amylopectin (“plant starch”) and acts as a secondary short-term energy storage for animal cells. It’s formed primarily in liver and muscle tissues, but is also formed at secondary sites such as the central nervous system and the stomach. In both cases it exists as free granules in the cytosol. Glycogen is a crucial element of the glucose cycle as another enzyme, glycogen phosphorylase, cleaves off glycogen from the nonreducing ends of a chain to producer glucose-1-phosphate monomers. From there, the glucose-1-phosphate monomers have three possible fates: (1) enter the glycolysis pathway as glucose-6—phosphate (G6P) to generate energy, (2) enter the pentose phosphate pathway to produce NADPH and pentose sugar, or (3) enter the gluconeogenesis pathway by being dephosphorylated into glucose in liver or kidney tissues. To initiate the process of glycogen chain-lengthening, glycogenin is required because glycogen synthase can only add to existing chains. This action is subsequently followed by the action of glycogen synthase which catalyzes the formation of polymers of UDP-glucose connected by (α1→4) glycosidic bonds to form a glycogen chain. Importantly, amylo (α1→4) to (α1→6) transglycosylase catalyzes glycogen branch formation via the transfer of 6-7 glucose residues from a nonreducing end with greater than 11 residues to the C-6 OH- group in the interior of a glycogen molecule.