Hormones, formerly known as "hormones".Human and animalEndocrine organOr the tissue is directly secreted tobloodA substance that has special effects on the body.digestive tractOrgans andplacentaSuch tissues also secrete hormones, such as pancreatic secretion hormone, gastric secretion hormoneChorionic gonadotropinEtc.The coordination of various hormones is necessary to maintain the metabolism and function of the body.In terms of chemical properties, some hormones are amine derivatives, such asadrenaline、thyroxineEtc;Some arepolypeptideorprotein, such as pituitary hormone releasing factorPituitary hormone、insulin、Glucagon、Calcitonin、parathyroid hormoneEtc;Some are steroid compounds, such asandrogen、estrogen、Adrenocortical hormoneEtc.Many hormone preparations and synthetic products have important uses in medicine and animal husbandry.[1-2]
Hormones, originally meaning "rising up" in Greek, play an important role in regulating the metabolism, growth, development, reproduction, gender, sexual desire and sexual activity of the body.
Hormones are chemical information substances synthesized by highly differentiated endocrine cells and directly secreted into the blood. They affect the physiological activities of the human body by regulating the metabolic activities of various tissues and cells.Hormones are highly effective bioactive substances secreted by endocrine glands or endocrine cells, which act as messengers to transmit information in the body and regulate physiological processes of the body.It is an important substance in our life.
Physiological significance
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Endocrine cells produce a class of chemicals with high efficiency in information transmission.Hormones have many kinds and very few quantities (most of them are at the level of nanogram or even microgram). They are neither the energy source of the body nor the structural substances that make up the body. But they play an important role in coordinating the metabolism, growth and development and other physiological processes through the transmission of information. No wonder scientists call them "first messengers".There are three main ways of hormone transmission: most hormones enter the blood directly after being secreted, and only when they reach certain tissue cells with blood circulation can they function. These cells are called target cells. There are substances with special three-dimensional configurations (hormone receptors) on the target cells that combine with the corresponding hormones, recognize the information carried by hormones, and transform it into a series of complex chemical reactions in cells,So as to produce specific physiological effects.Hormones in this way reach target cells with blood flow, so they are called "telesecretion".After some hormones are secreted, they diffuse through the interstitial fluid and act on adjacent cells (such as some digestive tract hormones), which is called paracrine.Other hormones are secreted by nerve cells (following the thalamus), called "neurohormones". They flow along the axon and reach the target cells through the axoplasm, which is called "neurosecretory".According to its chemical nature, hormones can be divided into nitrogen containing protein hormones (derived from amino acids, peptides and proteins) andsteroidHormone like two major categories;In terms of its physiological functions, it can be divided into three categories: one is to regulate the metabolism of the body and maintain the relatively stable internal environment, such as insulin, gastrointestinal hormone, parathyroid hormone, etc;One is to promote cell proliferation and differentiation, control body growth and development and reproductive function, and affect its aging process, such as growth hormone, sex hormone, etc;Another group works closely with the nervous system to enhance the body's adaptation to the environment, such as adrenocortical hormone and pituitary hormone.Too much or too little hormone secretion will cause disorder of body function, so the determination of hormone level is often used as the basis for diagnosis of some diseases in clinic, and many hormones are used as therapeutic drugs in clinic.In recent years, the principle of genetic engineering has been successfully applied to enable microorganisms to produce human hormones, such as insulin and other hormones through Escherichia coli, which has opened up broad prospects for the application of hormones in medicine, industry, agriculture and animal husbandry.
