Hormone: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Last updated

Nov. 8, 2026

News •

Cortisol being 'wrongly blamed' for health issues, experts say • Nov. 3, 2026, 6:02 PM ET (ABC News (Australia))

New report urges unified lifecycle approach to women's heart health • Oct. 26, 2026, 1:46 PM ET (News-Medical)

Photos and Videos

steroid hormones

neurosecretory cell

Labeled diagram of a mammalian pituitary gland showing key structures, including the paraventricular and supraoptic nuclei, neurosecretory cells, blood vessels, and pathways for hormone release and blood flow.

Two visualizations of human growth hormone: at left, a dense space-filling all-atom model with colored spheres; at right, a blue and white ribbon diagram showing the protein's structure.

Gonadotroph cell

Diagram showing the relationships among vertebrate endocrine glands, including the pituitary-hypothalamus system, pituitary hormones and their endocrine targets, and feedback loops. Arrows connect the hypothalamus and pituitary to glands such as the thyroid, ovary, testis, adrenal cortex, adrenal medulla, parathyroid, ultimobranchial gland, gastrointestinal organs, and pancreas, with major hormones labeled for each gland.

parafollicular cell; thyroid gland

Diagram showing a cross-section of a pancreatic islet of Langerhans on the left, with alpha, beta, and delta cells labeled by color, and on the right, arrows illustrating paracrine interactions among these cell types through hormones glucagon, insulin, and somatostatin.

An anatomical illustration of the human pancreas shows its location near the stomach and intestines, a detailed cross-section highlighting ducts and the islet of Langerhans, and an inset of pancreatic tissue histology with labeled alpha, beta, and delta cells.

Diagram showing the location of the adrenal glands above the kidneys in the human body, with a detailed cross-section labeling the capsule, adrenal cortex with its three zones (zona glomerulosa, zona fasciculata, zona reticularis), and the adrenal medulla.

Learn the importance of the ten glands of the human endocrine system

See All Videos and Images →

Topics

protein hormone ectopic hormone production permease pituitary hormone growth regulator thyroid hormone tropic hormone leptin digestive hormone adrenal hormone Protein Lipid carboxylic acid hydrocarbon heterocyclic compound organosulfur compound Nucleic acid Carbohydrate Steroid organometallic compound

Dig Deeper: More Articles That Discuss This Topic

Key People

Andrew V. Schally

Andrew V. Schally

American endocrinologist

Svetlana Mojsov

Svetlana Mojsov

Yugoslavian-born Macedonian American chemist

Starling

Ernest Henry Starling

British physiologist

default image

Sir William Maddock Bayliss

British physiologist

Percy Julian

Percy Julian

American chemist

Charles B. Huggins at work in a laboratory at the University of Chicago, c. 1965.

Charles B. Huggins

American surgeon and medical researcher

Roger Guillemin

Roger Guillemin

American physiologist

Charles-Édouard Brown-Séquard

Charles-Édouard Brown-Séquard

French physiologist

default image

F.A.F.C. Went

Dutch botanist

default image

George Washington Corner

American anatomist and embryologist

default image

Joshua Harold Burn

British pharmacologist

Sir Edward Albert Sharpey-Schafer.

Sir Edward Albert Sharpey-Schafer

British physiologist and inventor

Superficial arteries and veins of face and scalp, cardiovascular system, human anatomy, (Netter replacement project - SSC)

The Human Body

Muscles of facial expression, human anatomy, (Netter replacement project - SSC). Human face, human head.

Characteristics of the Human Body

Male muscle, man flexing arm, bicep curl.

Facts You Should Know: The Human Body Quiz