Effects on health
Although the amount of hormones in the human body is not much, it has a great impact on health. Insufficient or excessive secretion of growth hormone can cause various diseases, such as gigantism; Too little secretion can cause dwarfism. Excessive thyroid secretion can cause palpitations, sweaty hands and other symptoms; Too little secretion can easily lead to obesity and lethargy. Insufficient insulin secretion can lead to diabetes. Many hormone preparations and synthetic products have important uses in medicine and animal husbandry.
Substances that are directly secreted into the blood by endocrine gland organs of human beings and animals and have special effects on the body. The digestive tract organs and placenta can also secrete hormones, such as pancreatic secretion hormone, gastric secretion hormone and chorionic gonadotropin.
Action characteristics
1. High specificity includes tissue specificity and effect specificity. The former means that hormones act on specific target cells, target tissues and target organs. The latter means that hormones selectively regulate specific links in the process of gratitude for a generation. For example, glucagon, adrenaline and glucocorticoids all have the function of raising blood sugar, but glucagon mainly acts on liver cells, and directly transports glucose into the blood by promoting the decomposition of hepatic glycogen and strengthening gluconeogenesis; Adrenaline mainly acts on skeletal muscle cells, promotes muscle glycogen decomposition and indirectly supplements blood sugar; Glucocorticoid supplements blood sugar mainly by stimulating skeletal muscle cells, decomposing protein and amino acids, and promoting gluconeogenesis of liver cells. The role of hormones begins with the combination of hormones and receptors. Specific sex hormone binding proteins mediated by target cells are called hormone receptors. Receptors are generally glycoproteins, some of which are distributed on the surface of target plasma membrane, called cell surface receptors; Some are distributed inside cells, called intracellular receptors, such as thyroxine receptors.
2. Very efficient hormones have high affinity with receptors, so hormones can combine with receptors at very low concentrations to produce regulatory effects. The concentration of hormones in the blood is very low. Generally, the concentration of protein hormone is10-10-12 mol/L, and other hormones are10-6-10-9 mol/L. Moreover, hormones play a role by adjusting the amount and activity of enzymes, which can amplify the regulatory signal. The intensity of hormone action is related to the number of complex between hormone and receptor, so maintaining appropriate hormone level and receptor number is a necessary condition to maintain the normal function of the body. For example, insufficient insulin secretion or insulin receptor deficiency can lead to diabetes.
3. The multi-level regulation of endocrine regulation is multi-level. Hypothalamus is the highest center of endocrine system. It controls the hormone secretion of the pituitary gland by secreting neurohormones, that is, various release factors (RF) or release inhibitory factors (RIF), and the pituitary gland controls the hormone secretion of the thyroid gland, adrenal cortex, gonads and islets by releasing gonadotropins. There is a relationship between control and controlled between related levels, but the controlled can also react to the controller through feedback mechanism. For example, the hypothalamus secretes thyrotropin-releasing factor (TRF), which stimulates the anterior pituitary gland to secrete thyrotropin (TSH), so that the thyroid gland secretes thyroxine. When the concentration of thyroxine in blood rises to a certain level, thyroxine can also feedback and inhibit the secretion of TRF and TSH. The role of hormones is not isolated. Endocrine system not only has the control and feedback relationship between superior and subordinate, but also many hormones play a regulatory role at the same level. The interaction between hormones has both synergistic and antagonistic effects. For example, blood sugar regulation, glucagon and so on raise blood sugar, and insulin lowers blood sugar. They interact to stabilize blood sugar at a normal level. The two hormones that positively and negatively regulate a physiological process maintain a certain balance, and once broken, it will lead to endocrine diseases. The synthesis and secretion of hormones are regulated by the nervous system.