A hormone is a chemical mediator that is formed and secreted by some specialized glands.
These glands are called endocrine glands. They are also formed by a few cells especially the nerve cell.
They regulate the cell and body physiology.
To have an idea of all the hormones in the body, read the article list of hormones in the body.
The hormones can be differentiated based on the chemical structure, mode of action, organ secreting them, etc.
The different types of hormones:
Based on chemical nature the hormones are divided as
- Thyrotropin-releasing hormone
- Corticotropin-releasing hormone
- Growth hormone-releasing hormone
- Growth hormone inhibitory hormone (somatostatin)
- Gonadotropin-releasing hormone
- Growth hormone
- Thyroid-stimulating hormone
- Adrenocorticotropic hormone
- Follicle-stimulating hormone
- Luteinizing hormone
- Antidiuretic hormone or vasopressin
- Parathyroid hormone
- Human chorionic gonadotropin
- Human somatomammotropin
Their structure can be lengthy but is less complex. Their metabolism leads to the formation of amino-acids and then urea.
- Atrial natriuretic peptide
These hormones are steroidal. That is chemically they are formed from fats and lipids in the body. Their metabolism can lead to the formation of fatty acids and ketones.
- Dopamine or prolactin-inhibiting factor
- Thyroxine (T4) & triiodothyronine (T3)
These hormones are made of amines. Chemically their structure is simple.
Lack of hormones can lead to hormonal diseases in living beings. This deficiency may arise mostly due to improper diet, aging, and improper lifestyle. They are mostly long-standing and to rectify; they are to be supplemented externally.
Hormones are not limited to humans and animals alone. There are also hormones in plants, insects, and other smaller living organisms.