Mechanism of Hormone Action
Hormone receptors are the proteins present in the target tissue only. When they are present on the cell membrane of the target tissue, they are called membrane-bound receptors and the receptors present inside the target cell are called intracellular receptors. The mechanism of action of hormones is as follows:
- Hormones interacting with membrane-bound receptors: Binding of the hormone to its receptor leads to the formation of a hormone-receptor complex. After the formation of the complex, biochemical changes in the target tissue occur. On the basis of their chemical nature, hormones can be divided into groups:
- Peptide, polypeptide, protein hormones (e.g., insulin, glucagon, pituitary hormones, hypothalamic hormones, etc.)
- Steroids (e.g., cortisol, testosterone, estradiol and progesterone)
- Iodothyronines (thyroid hormones)
- Amino-acid derivatives (e.g., epinephrine).
- A secondary messenger is generated when hormones interact with the membrane-bound receptor.It can’t enter the target cell. This regulates cellular metabolism. For example, Cyclic AMP.
- Hormones interacting with intercellular receptors: Generally they regulate gene expression, or the hormone-receptor complex may interact with the genome through which chromosome functions. Example: Steroid hormone.
NCERT Notes for Class 11 Biology Chapter 19: Chemical Coordination and Integration
NCERT Notes Biology Class 11 Chapter 19 Chemical Coordination and Integration: The study of chemical coordination and Integration forms an important part of human physiology. Chemical coordination, integration, and regulations in the human body are carried out by special chemicals called hormones. Regulation, growth, and development of our organs, the endocrine glands, and cells are carried out by hormones.
Here, in Chapter 19 of Biology Class 11 NCERT Chemical Coordination and Integration, we will study the Human endocrine system, Hormones, and their mechanism of action.
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