Hormones are biologically active substances that play a crucial role in maintaining homeostasis and regulating various body functions, such as growth, metabolism, reproduction, and stress response. They are produced by different endocrine glands and organs, released into the bloodstream, and affect different tissues and systems. However, disruptions in hormone production can lead to serious diseases and disorders. This article reviews the main hormones, their effects on the human body, and the issues associated with their deficiency or excess.

Insulin and Glucagon

Insulin — is a hormone produced by the pancreas that lowers blood glucose levels by promoting its uptake into cells for energy use. It also plays a role in the metabolism of fats and proteins. A disruption in insulin production leads to type 1 and type 2 diabetes. In type 1 diabetes, the body is unable to produce insulin, requiring regular injections. Type 2 diabetes is related to insulin resistance, where cells do not respond properly to insulin.

Glucagon — is also produced by the pancreas and performs the opposite function of insulin by raising blood glucose levels through stimulating glycogen breakdown in the liver. An imbalance between insulin and glucagon can lead to hypoglycemia or hyperglycemia, which can impair brain function and damage other organs.

Cortisol and Adrenaline

Cortisol — the primary stress hormone, is produced by the adrenal cortex. It regulates metabolism, increases blood glucose levels, and has anti-inflammatory properties. Chronic elevation of cortisol, associated with prolonged stress, leads to hypercortisolism, which causes obesity, hypertension, and immune suppression.

Adrenaline (epinephrine) — produced by the adrenal medulla, mobilizes the body for the “fight or flight” response during stress. It increases heart rate, dilates airways, and boosts blood flow to muscles. Chronic overproduction of adrenaline can result in cardiovascular disorders, including hypertension and arrhythmia.

Triiodothyronine (T3) and Thyroxine (T4)

These hormones are produced by the thyroid gland and play a key role in regulating metabolism. They stimulate cellular metabolism and support the normal development and functioning of tissues. Deficiency in thyroid hormones (hypothyroidism) leads to reduced metabolism, fatigue, weight gain, and cognitive decline. Hyperthyroidism (excessive production of T3 and T4) causes accelerated metabolism, tachycardia, weight loss, and irritability.

Parathyroid Hormone and Calcitonin

Parathyroid hormone (PTH) — is produced by the parathyroid glands and regulates blood calcium levels by releasing calcium from bones and promoting its reabsorption in the kidneys. Disruptions in PTH production lead to hypo- or hypercalcemia, which can cause osteoporosis, muscle cramps, and cardiac arrhythmias.

Calcitonin — produced by the thyroid gland, lowers blood calcium levels by promoting its deposition in bones. Abnormal calcitonin secretion can contribute to the development of osteopenia or osteoporosis.

Pituitary Hormones

Growth Hormone (Somatotropin) — promotes tissue growth, particularly during childhood. Hyposecretion of growth hormone causes dwarfism, while its hypersecretion leads to gigantism in children or acromegaly in adults.

Prolactin — stimulates milk production in women. Excessive prolactin can cause galactorrhea (abnormal milk secretion), as well as menstrual irregularities and infertility.

Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) — These hormones regulate reproductive function in both men and women. Deficiency in LH and FSH leads to infertility and disorders of sexual development.

Sex Hormones: Testosterone, Estrogen, and Progesterone

Testosterone — is the primary male sex hormone that influences the development of secondary sexual characteristics and libido. Its deficiency leads to decreased sex drive, fatigue, and muscle mass loss. Excess testosterone can cause aggression and skin problems like acne.

Estrogen and progesterone — are key hormones in the female reproductive system, regulating the menstrual cycle and supporting pregnancy. Estrogen deficiency can lead to osteoporosis and cardiovascular disease, while its excess increases the risk of breast and uterine cancer. Disruptions in progesterone secretion can result in fertility and menstrual cycle problems.

Melatonin

Melatonin — secreted by the pineal gland, regulates circadian rhythms and sleep cycles. Melatonin deficiency can cause insomnia, while its excess can lead to disrupted wakefulness and general fatigue.

Hormones play a central role in regulating almost all aspects of physiological functioning. Disruptions in their production or action can lead to various disorders affecting metabolism, cardiovascular health, reproductive function, and mental well-being. Diagnosing and treating endocrine disorders requires a comprehensive approach that includes not only restoring normal hormone levels but also correcting the metabolic and functional imbalances associated with these disruptions.