What does calcitonin mean?
Calcitonin is a naturally occurring peptide hormone produced by the parafollicular, or C, cells of the thyroid gland. Its principal role is to regulate calcium in the blood: it lowers elevated calcium levels chiefly by slowing the breakdown of bone and encouraging the kidneys to excrete calcium. Although discovered relatively recently, in the early 1960s, calcitonin quickly became important in both physiology and clinical practice. Physicians measure its concentration in serum as a sensitive marker for medullary thyroid carcinoma, a cancer arising from the very cells that produce it. A pharmaceutical form, usually derived from salmon — whose calcitonin happens to bind human receptors more strongly than the human hormone itself — has been used to treat osteoporosis, Paget's disease of bone, and dangerous hypercalcemia. The word belongs firmly to medical and scientific registers and rarely surfaces outside discussions of hormones, bones, or thyroid disorders, yet it remains an essential term in endocrinology.
nounA peptide hormone produced by the parafollicular (C) cells of the thyroid gland that lowers blood calcium levels by inhibiting bone resorption and promoting calcium excretion by the kidneys.
- The calcium-lowering peptide hormone secreted by the C cells of the thyroid gland in mammals.
- A pharmaceutical preparation of this hormone (typically of salmon origin) used to treat osteoporosis, Paget's disease of bone, and hypercalcemia.
"The endocrinologist prescribed salmon calcitonin to help slow the progression of the patient's osteoporosis."
"Elevated serum calcitonin levels are a key marker in screening for medullary thyroid carcinoma."
"Because human calcitonin has a short half-life, synthetic salmon calcitonin was developed for therapeutic use."
Calcitonin is normally treated as an uncountable mass noun. A plural is occasionally seen when distinguishing different species variants (e.g. human, salmon, porcine calcitonins), but this is uncommon outside specialist biochemistry literature.
"Researchers compared the receptor-binding affinities of human and salmon calcitonins."
Calcitonin is one of the rare drugs extracted from fish — the salmon version is actually more potent in humans than our own hormone, because it binds human receptors more strongly.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of calcitonin
The term calcitonin was coined in the early 1960s following the hormone's identification as the calcium-lowering agent long suspected to exist alongside parathyroid hormone. The name combines 'calci-' (from Latin 'calcis', genitive of 'calx', meaning limestone or lime, via which English also derives 'calcium') with '-tonin', a suffix used for substances exerting a regulatory influence on tone or activity. It shares this Latin root with related terms such as 'calcium', 'calcareous', and 'calcify'.
How calcitonin is actually used
Calcitonin is almost exclusively used in medical and biochemical contexts — clinical medicine, endocrinology, and physiology. In everyday language it appears only when discussing thyroid conditions or bone disease. The older name 'thyrocalcitonin' still appears in some literature but 'calcitonin' is now standard. The term is uncountable as a hormone; specific pharmaceutical products may be referred to with brand names.
Easily confused with calcitonin
Melatonin is a hormone from the pineal gland that regulates sleep, whereas calcitonin is a thyroid hormone that regulates blood calcium levels.