Hormone

Hormone the hormone is a type of signaling molecule known as a chemical messenger. As the name suggests, the hormones act as a messenger by transporting a signal from the site of their secretion to the distant target organs to exert their biological functions. Hormones are essential system components and are required for the correct development of multicellular organisms (animals, plants, and fungi). Hormones could be classified into subgroups based on their involvement in various functions and processes, including metabolism, development, growth, reproductive activities, cognitive function, maintenance of body temperature, etc. Hormones are at the interface of effective communication between organs and tissues.

Hormones are secreted directly into the circulation from the ductless endocrine glands (Adrenal, Pituitary, Pancreas, Thymus, Thyroid, Testes, Ovaries, etc) of the body. These organs secrete hormones in tiny amounts, sufficient for their activities in regulating diverse body functions. Even a very slight change in the hormonal homeostasis could lead to the development of diseases. Hormones exert their biological functions through their interactions with specific receptors in their target cells. The hormone-receptor complex formed through this interaction then transmits signals to the target cells through a cascade pathway, regulating the expression of the target genes and their protein products. Due to the bipolar nature of the lipid membrane of the living cells, the soluble lipid hormones (such as steroids) directly act within the nuclei of the target cells. To mimic their roles in maintaining biological processes, many hormones and their structural and functional analogs are often used for therapeutic purposes. The most common examples of these hormones are estrogens and progestogens, which are used as hormonal contraception and as Hormone Replacement Therapy. Thyroxine (used for the treatment of hypothyroidism) and steroids (used for the treatment of autoimmune diseases and several respiratory disorders) are also frequently prescribed hormones. Insulin is one of the most commonly administered hormones, which many people with diabetes use the control blood sugar levels. [Md. Ismail Hosen]