Changes

==Description==

==Description==

Bile acids are synthesised from cholesterol in the liver and are then conjugated with glycine or taurine.  Feline bile acids are conjugated exclusively with taurine, partly explaining their high absolute requirement for this aminosulphonic acid.  In contrast, rabbits conjugate their bile acids only with glycine.  The conjugated bile acids are secreted into bile which then passes into the small intestine.

Bile acids are synthesised from cholesterol in the liver and are then conjugated with glycine or taurine.  Feline bile acids are conjugated exclusively with taurine, partly explaining their high absolute requirement for this aminosulphonic acid.  In contrast, rabbits conjugate their bile acids only with glycine.  The conjugated bile acids are secreted into bile which then passes into the small intestine.

==Clinical Significance==

==Clinical Significance==

The competence of the enterohepatic circulation is usually assessed by performing a bile acid stimulation test, where an animal fasted for 12 hours is then fed a test meal and the serum bile acid concentration is measured before and two hors after the meal.  The post-prandial measurement may be '''elevated''' in the following conditions:

The competence of enterohepatic circulation is usually assessed dynamically by performing a bile acid stimulation test; the patient is fasted for 12 hours and then fed a test meal and the serum bile acid concentration are measured before and two hours after the meal.  The post-prandial measurement may be '''elevated''' in the following conditions:

*'''Hepatobiliary disease''', but the type of disease cannot be determined from this finding alone.

*'''Cholestasis''', including the mild cholestasis that occurs due to hepatic hydropic change in [[Canine Hyperadrenocorticism - Cushing's Disease|hyperadrenocorticism]] in dogs and [[Biliary Tract - Obstruction|extra-hepatic biliary obstruction]].

*'''Hepatobiliary disease'''; this is a non specific test for hepatobiliary disease.

*'''Cholestasis''', including the mild cholestasis that occurs due to hepatic hydropic change in [[Hyperadrenocorticism|hyperadrenocorticism]] in dogs and [[Biliary Tract Obstruction|extra-hepatic biliary obstruction]].

*[[Portosystemic Shunt|'''Portosystemic shunts''']] or [[Hepatic Microvascular Dysplasia|'''microvascular dysplasia''']], in which the portal blood is directed into the systemic circulation, disrupting the enterohepatic circulation.

*[[Portosystemic Shunt|'''Portosystemic shunts''']] or [[Hepatic Microvascular Dysplasia|'''microvascular dysplasia''']], in which the portal blood is directed into the systemic circulation, disrupting the enterohepatic circulation.

*[[Antibiotic Responsive Diarrhoea|'''Small intestinal bacterial overgrowth''']] due to deconjugation of bile acids by intestinal bacteria.

*[[Antibiotic Responsive Diarrhoea|'''Small intestinal bacterial overgrowth''']] due to deconjugation of bile acids by intestinal bacteria.

*Increased post-prandial bile acid concentration may be a normal finding in '''Maltese terriers'''.

*Increased post-prandial bile acid concentration may be a normal finding in '''Maltese terriers'''.

'''Deficiency''' of bile acids is extremely rare, even with severe hepatic insufficiency.

'''Deficiency''' of bile acids is extremely rare, even with severe hepatic insufficiency.

[[Category:Blood Biochemistry Changes]]

[[Category:Blood Biochemistry Changes]]