Chemical Classes of Hormones, Hormones are chemical messengers that are secreted directly into the blood, which carries them to organs and tissues of the body to exert their functions. There are many types of hormones that act on different aspects of bodily functions and processes. Source
There are 3 chemical classes of hormones. Namely;
- Steroid hormones.
All these classes differ on the basis of chemical composition.
Amines are derives of thyrosin, including thyroid hormones, epinephrine, norepinephrine and dopamine. Thyroid hormone in the body is stored as thyroglobulin, that is; it is stored in the form of thyroid within the follicles of thyroid gland. Thyroglobulin will break into protein chains and thyroxine when some stimulus comes. It then enters the blood by exocytosis. In this form it can perform its function for about 4 to 6 weeks, meaning that it will remain active.
Peptides are proteins in nature. They are composed of different amino acids other than thyrosine. These amino acids are bound to each other in a specific sequence through peptide bonds. They are larger in size but smaller than the proteins.
Steroids are derivatives of cholesterol. They are not stored as they are lipid soluble and thus can pass the cell membrane. They are formed when the stimulus is received and are released directly into the blood. They have large lasting effect. These are composed of three cyclo hexyl rings and one cyclopentyl ring. They remain the same but the difference in them arises on the basis of the functional group attached to them. It includes; adrenal cortex hormones, gonads and placental hormones.
Duration of action of hormones:
The time required for hormones to show their function is different.
Mostly stress hormones (epinephrine and norepinephrine) are formed in 1 second. After 1 minute, their function is completed and the stress hormones are degraded. It is the smallest time of hormones’ action.
However, on the other hand thyroid hormones may take 4 to 6 weeks to show and complete their function.
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