Metabolism

Metabolism refers to the sum of all the chemical reactions necessary for the body to sustain life. From a small scale, there are various aspects of metabolism: energy metabolism, gas metabolism, amino acid metabolism, sugar metabolism, etc., in the field of toxicology. It refers to the metabolic transformation of exogenous and non-enzymatic reactions of exogenous chemicals in the body, also known as biotransformation. Biotransformation can be divided into a first phase reaction and a phase II reaction. Most exogenous chemicals undergo two-phase reactions, but a few are only one of the two phases. As a result of the first phase reaction, water solubility is increased and it is easy to be discharged with urine. The Phase II reaction further increases water solubility and may increase the molecular weight (eg, glucuronide formation or binding to glutathione). When the conjugate has a molecular weight of more than 325, it is easy to be discharged into the intestine with bile. In addition to making exogenous chemicals readily excreted, they are often inactivated or reduced in activity due to changes in chemical structure. Therefore, metabolic transformation is often considered to be detoxication. But sometimes the opposite result increases toxicity, called toxication or activation or bioactiva-tion. The metabolism of most poisons in the body not only participates in a single reaction, but multiple reactions in succession. The activation of a chemical may be the result of one of the reactions, or it may be a summary of a series of reactions, or it may be detoxified after activation. The reaction product of metabolic conversion is called metabolite. A chemical can have a variety of metabolites, some of which are reactive metabolites with varying levels of activity. The two-phase reaction mostly involves an enzymatic reaction. These enzymes are often referred to collectively as metabolic enzymes, toxic metabolic enzymes or drug metabolizing enzymes. See induction of enzymes, induction of enzymes. Energy metabolism refers to the process of energy production and consumption in the process of metabolism (metabolism) of the body. Material metabolism is the most basic feature of life activities shared by all living organisms. The process of material metabolism can be divided into two aspects: on the one hand, anabolism, ie assimilation, including the formation and repair of body tissues and storage of energy; on the other hand, catabolism, ie, dissimilation, including tissue decomposition and energy consumption. The sum of anabolism and catabolism is called material metabolism. Generally speaking, when catabolism, the macromolecule of the substance is decomposed into small molecules, in which the chemical energy in the storage macromolecule is released; while in anabolism, the small molecule becomes a macromolecule, and this process requires energy. Must be obtained from catabolism. The energy released by catabolism, in addition to the supply of anabolic, is converted into heat and mechanical energy, and there is still radiant energy and electrical energy. Therefore, the metabolism of matter is inevitably accompanied by the transfer of energy. The process of energy conversion of this organism is called energy metabolism.