Hormone is a regulatory substance produced in an organism and transported in tissue fluids such as blood to stimulate specific cells or tissues into action.
4 Types of Hormones
There are four different types of hormones. These hormones are grouped by the chemicals from which they are made. The four types are;
- Eicosanoids- they are hormones made from lipids. They send messages near the cells that make the hormones.
- Amino acid derived hormones- these are hormones that one nerve cell sends to another. Most of them are neurotransmitters.
- Peptides, polypeptides and protein hormones- examples of such hormones include growth hormones and insulin
- Steroid hormones- these hormones are derived from cholesterol. They include testosterone and estradiol.
Classification of Hormones
Hormones are classified into five different categories. The categories include:
- According to chemical nature
- According to mechanism of action
- According to nature of action
- According to the effect and
- According to their stimulation of Endocrine glands.
1. According to Chemical Nature.
Hormones in this category include;
- Steroid hormones- they are made up of lipids which are derived from cholesterol e.g. progesterone and estrogen
- Peptide hormones- they are made up of few amino acid residues e.g. oxytocin
- Protein hormones- they are also made of amino acid residues e.g. insulin, glucagon
- Glycoprotein hormones- they are glycoprotein in nature and are made of conjugated proteins e.g. galactose
- Eicosanoids hormones- they are small fatty acid derivatives e.g. prostaglandins
- Amine hormones- they are made up of amines. The hormone is a derivative of amino acid tyrosine e.g. epinephrine and norepinephrine
2. According to Mechanism of Action
Hormones in this category are grouped into two groups;
- Group I hormones- these hormones are lipophilic in nature and bind into intracellular receptors to form hormone-receptor complexes e.g. estrogen, progesterone, testosterone
- Group II hormones- the hormones are lipophilic and are transported in free form. They possess a short half-life. They include FSH, LH, phospholipid, GnRH, gastrin, insulin, oxytocin etc.
3. According to Nature of Action
Hormones in this category include;
- Local hormones- they have specific local effect e.g. testosterone
- General hormones- they are transported by circulation to the target tissues and organs e.g. insulin, thyroid hormone etc.
4. According to the Effect
- Metabolic hormones- these hormones are responsible for metabolic changes and reaction balance e.g. insulin and glucagon
- Kinetic hormones- these hormones causes muscle contraction, glandular secretion e.g. epinephrine
- Morphogenetic hormones- they are involved in growth and differentiation e.g. thyroid hormone, FSH, LTH
5. According to their stimulation of Endocrine glands
Tropical hormones – the hormones stimulate other endocrine glands for secretion e.g. TSH stimulates secretion of thyroid gland.
Functions of different types of hormones
Hormones have five main functions. These functions are:
- Hormones are responsible for sending chemical signals to every part of the body.
- They are responsible for bodily changes especially during puberty
- They play an important role in the development of muscles and bones of the body.
- They act to control metabolism and balance body reactions
- They are important in maintaining hemostasis.
Different Types of Female Hormones and Their Functions
There are two main types of hormones that are considered female. They are estrogen and progesterone
The hormone is produces by the ovaries and the adrenal gland
- It favors the formation and growth of bones.
- It stimulates the formation of protein
- It is responsible for soft texture of the skin
- Estrogen is responsible for increase in size of female reproductive organs
This hormone is produced in large amounts during and after ovulation to prepare the uterus for implantation. Its functions include
- It reduces uterine contractions to prevent the fertilized egg from being expelled.
- It is also responsible for development of breast cells that secretes milk
- It increases the excretion of water and salt.
List of Hormones in The Body and Their Functions
- Luteinizing Hormone- promote ovulation in females and promotes testosterone release in males
- Follicle Stimulating Hormone- promotes development of eggs and follicles in females and promotes testosterone release from testes in males.
- Growth hormone- act to promote growth of bones and organs
- Prolactin- stimulates milk production in the breast.
- Oxytocin- causes ejection of milk from the milk ducts
- Thyroxine and Tri-iodothyronine- regulates the body’s metabolic rate.
- Aldosterone- acts to maintain blood pressure
- Insulin- lowers blood glucose levels
- Estrogen- promote development of primary and secondary sex characteristics. Also prepares the uterus for implantation
- Progesterone- important in maintenance of pregnancy
- Testosterone- promotes development of male sexual characteristics
There are several hormones in the body. nexelmedical.com outlines them very well.