The hormones form part of a human’s endocrine system. This system regulates the amount of hormones produced and released as the need arises. The endocrine system is also responsible for maintaining a balance in the hormonal system to ensure all processes are functioning optimally. The endocrine system is regulated by an axis known as the hypothalamus-pituitary axis which originates in the brain in the hypothalamus and moves to the pituitary gland which then stimulates all endocrine organs or glands to release their hormones.
All these hormones play a pivotal role in maintaining the normal functioning of the processes in the body. It is important that a balance be maintained between these hormones because if there are any problems present at any stage, it can influence an individual’s health and quality of life.
Thyroid Hormones
Thyroid hormones are hormones that are produced and released via the thyroid gland which is situated in the front part of the neck just below the Adam’s apple. This gland produces four hormones namely: Thyroxine (T4), triiodothyronine (T3), reverse triiodothyronine (rT3) and calcitonin. These hormones play an extremely important role in regulating one’s metabolism while calcitonin helps to maintain the calcium balance in the body. They assist in maintaining a normal body temperature.
T4 is seen as a pre-active form of thyroid hormone as it is metabolised in the bloodstream to T3 before it can be absorbed and used. T3 is available in less amounts than T4 but is rapidly absorbed. These hormones require adequate iodine concentrations in the body in order to produce these hormones. Iodine is usually found in supplements or via certain food types such as table salt, seaweed and shellfish. The recommended daily allowance of iodine for optimal thyroid function is about 150 – 200 micrograms per day.
Reverse T3 is seen as an inactive byproduct from the metabolism of T4 to T3. Calcitonin plays a role in decreasing calcium in the body when these concentrations are too high. It helps to reduce calcium in the bloodstream, reduce the absorption thereof in the intestines, increase secretion via the urine and inhibit the breakdown of bones.
Insulin
Insulin is a peptide hormone that is released from cells within the pancreas. It is usually secreted as a response to high blood glucose levels and works by stimulating the uptake of these glucose molecules as they serve as a form of energy. Insulin also assists with the metabolism of carbohydrates, lipids and protein. Insulin can also be stimulated via the response of growth hormones and cortisol. When insulin is stimulated due to glucose, it is secreted in three phases. The first phase is quite quick and does not last long and is also not dependent on the amount of glucose consumed. The second phase is a response on the amount of glucose consumed while the third phase has a duration of about 90-120 minutes where insulin is being secreted. Maintaining a healthy lifestyle is important in order to ensure that the insulin secretions still work optimally and that the cells which are supposed to uptake the insulin also function properly in order to avoid the development of diabetes.
Cortisol
Cortisol is a steroid hormone that is produced and released by the adrenal gland which is situated on the top part of the kidneys. It is usually released as a response when the body is experiencing stress, but it also has other functions such as decreasing inflammation in the body and working along the pancreas to regulate blood sugar. It also plays a role in maintaining the cycle of waking and sleeping. When the sun rises cortisol levels will rise which helps an individual to feel “awake”, however, cortisol levels slowly decrease during the day and when the sun starts to set it will stimulate the release of melatonin which will make an individual feel sleepy. This is regulated by the circadian rhythm.
Reproductive Hormones
Reproductive hormones, such as estrogen and testosterone, play crucial roles in regulating sexual development, reproductive functions, and fertility in both males and females. These hormones influence processes like the menstrual cycle, pregnancy, and the development of secondary sexual characteristics.
Testosterone
Testosterone is the reproductive hormone that is dominant in males, however, females also have testosterone, which is just present at lower levels. Testosterone is produced in the testis and plays an important role in the production of sperm as well as in maintaining healthy sperm in order to ensure optimal male fertility. It also plays a role in the development of secondary sexual characteristics when a male reaches puberty, such as the growth of body and facial hair, deeper voice, increased muscular mass and a higher level of libido. Testosterone typically gradually decreases when a man reaches the age of 35 years.
Oestrogen And Progesterone
Oestrogen is the reproductive hormone that is dominant in females and similarly, men also have oestrogen, just in lesser amounts. Oestrogen plays an important role in the development of secondary sexual characteristics such as the development of breasts, the growth of pubic hair and the initiation of the menstrual cycle. It plays a role in maintaining the menstrual cycle along with progesterone and also helps to optimise fertility. It also has an important role to fulfil in bone health by maintaining healthy bone metabolism which leads to strong and healthy bones. Progesterone helps to maintain the menstrual cycle and also plays a role during pregnancy. Progesterone helps to prepare the endometrium for implantation of a fertilised egg and also helps to uphold a pregnancy.
