Q.What are hormones? Give one example for each of the following:

Insulin is the peptide hormone secreted by the pancreas that lowers blood glucose.

Insulin is a small protein (peptide) hormone consisting of two polypeptide chains (A-chain and B-chain) linked by disulphide bridges. It is produced and secreted by the β-cells located in the islets of Langerhans within the pancreas, in response to rising blood glucose levels. Its main physiological role is to promote uptake of glucose by body cells (especially muscle and adipose tissue) and its conversion to glycogen, thereby lowering blood sugar concentration. A deficiency of insulin, or resistance to its action, causes diabetes mellitus.

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Glucocorticoids control carbohydrate (glucose) metabolism.

Hormones are the biomolecules that act as intercellular (cell-to-cell) chemical messengers.

Hormones are secreted directly into the bloodstream by endocrine glands and travel to distant target cells/organs, where they bind specific receptors and trigger a physiological response — this is precisely what 'intercellular messenger' means. DNA and RNA store and transmit genetic information (intracellular, not primarily messenger molecule …

Testosterone, the principal male sex hormone secreted by the testes, is responsible for the deepening of the voice and other male secondary sexual characters at puberty.

Testosterone is a steroid hormone produced mainly by the testes. During puberty, rising testosterone levels trigger the development of male secondary sexual characteristics — growth of facial/body hair, muscle development, and enlargement of the larynx (voice box) and thickening of the vocal cords, which together cause the voice to deepen …

Insulin is a peptide hormone secreted by the pancreas that regulates blood glucose levels.

Insulin is a small protein (a polypeptide made of two chains, 51 amino acids in total, joined by disulphide bridges) that is secreted by the beta cells of the pancreas. It functions as a hormone — it is released into the bloodstream and regulates carbohydrate (glucose) metabolism by promoting glucose uptake into cells, thereby lowering blood sugar levels. Deficiency of insulin, or the body's inability to respo …

Thyroxine, secreted by the thyroid gland, contains iodine and is essential for regulating metabolic rate.

Among the given hormones, adrenaline, testosterone and insulin do not contain iodine. Thyroxine is synthesised in the thyroid gland from the amino acid tyrosine and iodine obtained from the diet; each thyroxine molecule contains four i …

Insulin is the hormone that directly regulates and maintains blood glucose within its narrow normal range.

Insulin, secreted by the beta cells of the pancreas, is the hormone primarily responsible for lowering and regulating blood glucose levels — it promotes glucose uptake by cells and glycogen synthesis, keeping blood glucose within a narrow physiological range. (Its counter-regulatory hormone, glucagon, raises blood glucose when it falls too low.)

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Insulin, the blood-sugar-lowering hormone, is secreted by the beta-cells of the islets of Langerhans in the pancreas.

Insulin is a peptide hormone produced by the beta-cells of the islets of Langerhans in the pancreas. It lowers blood glucose by promoting its uptake and storage; its deficiency causes diabetes mel …

Thyroxine, secreted by the thyroid gland, is the hormone that contains iodine.

Thyroxine is an amino-acid-derived hormone built on a tyrosine backbone that is iodinated at several ring positions. It regulates the body's basal metabolic rate; a deficiency of iodine in the diet impairs thyroxine synthesis and can cause goi …

Thyroxine is the principal hormone secreted by the thyroid gland; it is derived from the amino acid tyrosine and contains iodine.

Hormones are chemical messengers secreted directly into the bloodstream by endocrine (ductless) glands, which regulate various body functions. Many hormones, like thyroxine, are amino-acid derivatives.

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Hormones are biochemical signalling molecules, secreted by ductless (endocrine) glands into the bloodstream, that regulate the physiology of target organs elsewhere in the body.

Hormones are produced in small amounts by specialised endocrine glands (e.g. pancreas, thyroid, adrenal glands, pituitary) and are released directly into the bloodstream, through which they travel to specific target tissues/organs where they bind to receptors and trigger a physiological response. Chemically, many hormones are proteins/peptides (e.g. insulin, which regulates blood glucose level, is a protein hormone made of two polypeptide chains), while others are steroids (e.g. testosterone, oestrogen) derived from cholesterol. Hormones act as chemical messengers that …