Table 1 Unusual bile salt profiles in reptiles and mammals
Bile salt pattern | Examples | Comment |
|---|---|---|
5α ('allo') bile acids | Lizards, especially Iguania | 5α bile acids are generally rare in vertebrates |
1α-Hydroxylation | Spotted cuscus (Phalanger maculatus) | Unusual hydroxylation leads to highly hydrophilic bile acids in this species. |
1β-Hydroxylation | Feather-tailed glider (Acrobates pygmaeus) | Unusual hydroxylation site |
6α-Hydroxylation | Suidae Lesser Malay chevrotain (Tragulus javanicus) | Unusual hydroxylation site. Hyocholic acid is only detected in Suidae and the chevrotain. |
6β-Hydroxylation | Muridae | Unusual hydroxylation site |
7-Oxo bile acids | Queensland koala (Phascolarctos adjustus) | Unusual bile salt modification |
15α-Hydroxylation | Common wombat (Vombatus ursinus) | Not seen in other mammals but found in birds |
16α-Hydroxylation | Snakes | Hydroxylation at 16α is common in snakes (Boidae, Cylindrophiidae, Pythonidae, Uropeltidae) and birds but not seen in mammals. |
Ursodeoxycholic acid (at > 5%) | Ursidae Caviomorph rodents | Ursodeoxycholic acid is seen in other mammals but only as a small percentage of the bile salt pool. |
Δ22 Bile acids | Agouti (Dasyprocta punctata) Mountain paca (Cuniculus taczonowskii) Pacharana (Dinomys branickii) Some snakes | This unusual bile acid side-chain modification is seen in a small number of mammals and is also found in some snakes in Colubridae. |
22-Hydroxylated C27 bile acids | Turtles | This type of bile salt is unique to turtles. |
23R-Hydroxylation | Pinnipeds Some snakes | 23R-Hydroxylation of bile acids is common to Pinnipeds but is not seen in other Carnivora. |
100% Bile alcohols | Paenungulates, rhinoceroses | Profile also seen in lobe-finned fish, jawless fish, some teleost fish, and some amphibians. |