Cortisol is a major hormone in the human body, synthesized primarily in the adrenal glands, a pair of endocrine glands situated right above the kidneys. It is commonly called the “stress hormone” as it possesses anti-inflammatory capabilities and stimulates the antistress mechanism, being released in times of physical strain, mental pressure and emotional burden. However, cortisol, a steroid hormone belonging to the glucocorticoid class of biochemical messengers produced in the adrenal cortex also carries out various other functions in the system. These include regulating metabolism and energy levels, bolstering immunity, controlling blood glucose levels and augmenting digestion processes in the stomach.
The concentration of cortisol circulating in the blood and other bodily tissues is monitored by the hypothalamus in the brain, the pituitary gland at the base of the skull and the adrenal gland, which are together termed as the HPA axis. Cortisol is generated in the zona fasciculata, the second layer of the adrenal cortex, which consists of the outer portion of each of the adrenal glands located over the kidneys. When corticotropin-releasing hormone (CRH) is formed in the hypothalamus in the brain, it stimulates the secretion of adrenocorticotropic hormone (ACTH) by the pituitary gland. This, in turn, triggers the production of cortisol by the adrenal glands and its subsequent release into the bloodstream. This series of biochemical reactions occur in the body during both, normal homeostasis conditions as well as in times of stress.
In most scenarios, this process of cortisol synthesis is highly regulated by the gland combination of the HPA axis, to ensure optimal metabolism, stress response and immunity. Yet, some instances such as viral fevers and traumatic experiences trigger harmful effects due to high levels of cortisol, while defects in the pituitary gland lead to reduced amounts of the hormone and health anomalies in the body.
Cortisol And Its Structure:
Cortisol was first isolated from adrenal extracts by the renowned American chemist Edward Calvin Kendall in the year 1946. Following this, the recognised American physician Philip Showalter Hench determined the therapeutic use of cortisol for application in human disease and medicine in 1948 – 1949. At this time, the reputed Polish-Swiss chemist Tadeusz Reichstein also successfully extracted glucocorticoid compounds from the adrenal tissues. For their pioneering experiments leading to the isolation and discovery of steroid hormone cortisol, these three famous scientists and medical professionals were awarded the Nobel Prize In Physiology Or Medicine in the year 1950.
Cortisol is fundamentally a steroid hormone categorized under glucocorticoids, which is a derivate of cholesterol, composed of carbon, hydrogen and oxygen molecules arranged in four rings in a particular configuration. This hormone possesses a molecular formula of C22H30O5 and bears a molar mass of 362.46 g/mol. (grams per mole, which is the international standard unit for measuring the atomic weight of chemical compounds).
Vital Functions Of Cortisol In The Human Body:
The key biological functions of cortisol in the human system include:
- Activating a prompt stress response when the body undergoes excessive strain, trauma or mental pressure
- Elevating memory and cognitive capacity in the brain
- Regulating gluconeogenesis i.e. the synthesis of new glucose molecules in the body
- Balancing the concentration of glucose or sugars in the bloodstream
- Preserving normal healthy blood pressure
- Controlling the inflammatory molecules in the system and boosting immune functions in times of disease
- Maintaining electrolyte balance of sodium and potassium ions, balancing their influx into and efflux out of cells
- Inducing gastric acid production in the stomach, to facilitate smooth digestion for a healthy gut
- Fostering optimal development of the foetus in pregnant women
Harmful Effects Of Hormonal Imbalance In Cortisol Levels:
High Levels Of Cortisol:
In cases where a tumour develops in the adrenal gland or anterior pituitary, vast levels of cortisol are released into the bloodstream, resulting in a condition known as Cushing syndrome. This invariably causes fatigue, fluctuations in body weight, weak bones and muscles, and can be treated by surgically removing the tumour growths in the glands, to restore normal hormone levels of cortisol.
Low Levels Of Cortisol:
Low cortisol levels arise from damage to adrenal glands, which fail to produce sufficient amounts of the hormone. This ailment is termed Addison disease or primary adrenal insufficiency and is an autoimmune disorder that causes severe exhaustion, decline in body strength and requires continuous medical care to alleviate the discomforting signs.