Cadmium: the pathway in the body

This page shows the biochemical pathway of the substance Cadmium: how it enters the body, which stations it passes and which steps it affects. Every statement has a source. The page describes general textbook knowledge and says nothing about any individual person.

In brief

Cadmium is a heavy metal with no known role in the body. It enters cells via transport routes for iron and zinc, is bound to metallothionein and is stored mainly in liver and kidney.

The pathway step by step

1. Cadmium in food → Into the gut cell DMT1 · Iron, Zinc Cadmium ions use transporters for iron, zinc and manganese, mainly DMT1 and the zinc transporters ZIP8 and ZIP14. This is called ionic mimicry. Source 1, 7, 6
2. Into the gut cell → Cadmium in blood In blood, cadmium is first bound to albumin and other proteins. In this way it mainly reaches the liver. Source 2
3. Cadmium in blood → Liver · Metallothionein In the liver, cadmium binds to metallothionein, a small protein with many cysteines. Part of this complex returns to the blood. Source 2, 3
4. Liver → Kidney Megalin, cubilin The cadmium-metallothionein complex is filtered in the kidney and taken back up in the first section of the renal tubules via the receptors megalin and cubilin. Source 2, 1
5. Cadmium in the cell → Binding to thiol groups Free cadmium binds to sulfhydryl groups (SH groups) of proteins. In this way it changes the shape and activity of these proteins. Source 5, 6
6. Binding to thiol groups → Zinc binding sites · Zinc Cadmium resembles zinc and takes its places in enzymes and in zinc-finger proteins. The zinc bound there is released. Source 4, 6
7. Zinc binding sites → New metallothionein Zinc and cadmium prompt the cell to make more metallothionein. The new protein binds free cadmium ions tightly. Source 3, 4
8. Binding to thiol groups → Glutathione complex · Glutathione Cadmium also binds to glutathione (GSH), the main thiol of the cell. Glutathione bound in this way is not available to the cell for other tasks. Source 5
9. Glutathione complex → Excretion Cadmium stays bound in kidney and liver for a long time. It leaves the body only slowly, mainly with the urine. Source 2

Cofactors in this pathway

• Zinc — Cadmium occupies zinc binding sites; zinc prompts the formation of metallothionein Source 4, 3In the ORY catalogue as a laboratory value: Zink
• Glutathione — Binds cadmium via its SH group inside the cell Source 5In the ORY catalogue as a laboratory value: Glutathion (GSH)
• Iron — Cadmium uses DMT1, the uptake route for divalent iron Source 7, 1In the ORY catalogue as a laboratory value: Eisen
• Calcium — Cadmium can use calcium channels as an entry route into the cell Source 1, 6In the ORY catalogue as a laboratory value: Calcium (intrazellulär)
• Cysteine — Provides the SH groups with which metallothionein binds cadmium Source 2, 3

Sources

1. Thévenod F, Fels J et al. Channels, transporters and receptors for cadmium and cadmium complexes in eukaryotic cells: myths and facts. Biometals 2019 · PubMed 30701379
2. Sabolić I, Breljak D et al. Role of metallothionein in cadmium traffic and toxicity in kidneys and other mammalian organs. Biometals 2010 · PubMed 20549307
3. Klaassen CD, Liu J et al. Metallothionein protection of cadmium toxicity. Toxicol Appl Pharmacol 2009 · PubMed 19362100
4. Brzóska MM, Moniuszko-Jakoniuk J. Interactions between cadmium and zinc in the organism. Food Chem Toxicol 2001 · PubMed 11524135
5. Cuypers A, Plusquin M et al. Cadmium stress: an oxidative challenge. Biometals 2010 · PubMed 20361350
6. Bridges CC, Zalups RK. Molecular and ionic mimicry and the transport of toxic metals. Toxicol Appl Pharmacol 2005 · PubMed 15845419
7. Shawki A, Knight PB et al. H(+)-coupled divalent metal-ion transporter-1: functional properties, physiological roles and therapeutics. Curr Top Membr 2012 · PubMed 23177986

Related pathways

• Blei — Zink, Glutathion (GSH)
• Nickel — Zink, Glutathion (GSH)
• Quecksilber — Zink, Glutathion (GSH)

As of 2026-09-18. Draft, written by Claude to schema v2; sources checked in PubMed; expert approval pending
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