What is the Origin of Enterohepatic Circulation of Sterols?

The term is rooted in classical human physiology, combining entero- (Greek for intestine) and hepatic (Greek for liver) with circulation (Latin circulatio for movement in a circle). Sterols refer to a class of naturally occurring steroids, including cholesterol and steroid hormones. This pathway was recognized as a key route for the body's lipid and steroid recycling.

What is the Mechanism of Enterohepatic Circulation of Sterols?

The liver conjugates steroid metabolites, such as estrogens, with glucuronic acid or sulfate, making them water-soluble for biliary excretion. Once in the gut, specific gut bacteria can deconjugate these metabolites via beta-glucuronidase enzymes, allowing the now fat-soluble steroids to be reabsorbed across the intestinal wall. Modulation of the gut microbiome or inhibition of the deconjugating enzymes can therefore be a therapeutic target to reduce the reabsorption and enhance the final clearance of these hormonal compounds.

Enterohepatic Circulation of Sterols ∞ Area

Enterohepatic Circulation of Sterols

Meaning

The enterohepatic circulation of sterols describes the physiological process where cholesterol and other steroid metabolites, including sex hormone conjugates, are secreted from the liver into the bile, pass into the small intestine, and are subsequently reabsorbed back into the systemic circulation. This cyclical pathway is crucial for maintaining cholesterol homeostasis and significantly influences the body’s overall exposure to certain hormone metabolites. An efficient clearance mechanism is necessary to prevent the prolonged recirculation of potentially undesirable or inactive steroid compounds, supporting optimal hormonal balance.