Hormones: Mechanism of Action and Effects on Tissues

Subject: Endocrinology
Pages: 1
Words: 360
Reading time:
2 min

Hormones are the substances making the living body alive; their mechanism of action is quite simple: they bind with their receptors and make them react in a particular way, initiating subsequent reactions. Hormones are produced by glands of the endocrine system of the organism and regulate all other systems. They are responsible for maintaining homeostasis and regulating different substances in the organism, for feelings and perception.

Endocrine glands produce hormones in response to some factor: this factor can be a stimulus from the environment, such as increased temperature or another hormone. Perceptions are based on the actions of the hormones: they activate specific parts of the organism’s tissues in response to a stimulus, and it feels like some particular perception (Davies, 2021). Hormones regulate the level of different components in the organism, such as calcium level in the blood, as shown in Figure 1 (Davies, 2021). They stimulate the growth of tissues and their differentiation to other tissues when it is necessary 2 (Belfiore & LeRoith, 2018). In that way, hormones are vital factors for maintaining the organism in the rights conditions.

Regulation of blood calcium level by parathyroid hormone, shown schematically
Figure 1. Regulation of blood calcium level by parathyroid hormone, shown schematically

Different hormones have different mechanisms of action, but they all are based on the interaction between a hormone and its receptor. Hormone’s binding to the receptor, located at the cell’s surface, leads to changes and subsequent reactions inside the cell, as shown in Figure 2 (Belfiore & LeRoith, 2018). Some hormones penetrate the cell and bind with receptors located in the cell nucleus: they have a more direct mechanism of action. Hormones are molecular “triggers,” turning on and off different organism systems and making them act necessarily.

The example of hormone-receptor binding and receptor's subsequent reaction, drawn schematically
Figure 2. The example of hormone-receptor binding and receptor’s subsequent reaction, drawn schematically

Hormones are an essential part of human life: they regulate the whole organism, from blood calcium level to feelings. Their mechanism of action is similar for different substances and based on hormone-receptor interaction and following receptor reactions. Those reactions lead to changes in corresponding tissue and, consequently, in the organism. Hormones are chemical switches that, together with their receptors, initiate necessary chemical reactions in different tissues.


Belfiore, A., & LeRoith, D. (2018). Principles of Endocrinology and Hormone Action (1st ed. 2018 ed.). Springer.

Davies, J. (2021). Human Physiology: A Very Short Introduction. Oxford University Press.