Library · Physiology
Enterohepatic circulation
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The body does not make all its bile fresh every time you eat. It recovers it. That loop is called the enterohepatic circulation, from entero, intestine, and hepatic, liver: bile salts go down into the intestine, do their job on fat, pass into the blood, and return to the liver, which secretes them again.
They are not picked up just anywhere. The salts stay in the small intestine while the fat is being absorbed, and at the very end, in the terminal ileum, active transport, that is, a mechanism that uses energy, recovers most of them.
The numbers are striking: about 95% comes back, and it is that return, more than what the liver makes fresh, that maintains the pool. They are the glasses at a party that get washed and go back to the table instead of being replaced every time.
In the intestine, the bacteria that live there modify some of those primary bile acids and turn them into secondary ones, so what comes back is not identical to what left.
In brief
The enterohepatic circulation is the loop by which bile salts return from the intestine to the liver and are secreted again.
The salts stay in the small intestine, and the terminal ileum reabsorbs most of them by active transport.
About 95% comes back, and that, more than hepatic synthesis, maintains the bile acid pool.
The glasses at a party that get washed and go back to the table instead of buying new ones every time.
Gut bacteria convert some of those primary bile acids into secondary ones.
Sources (2)
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Bile, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Bile Acids, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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