Bile Acids of Elasmobranch Fish

Abstract

THE bile of bony fishes, like that of birds and mammals, contains acids in which glycine or taurine is conjugated with mono-, di-, and tri-hydroxy derivatives of cholanic acid. On the other hand, Hammarsten¹ isolated from the bile of the shark, Scymnus borealis, acids which he showed to be sulphuric esters of neutral compounds, chiefly α-scymnol. The constitution of scymnol has been largely elucidated by the investigations of Windaus, Bergmann and König², and of Tschesche³, who have shown that the compound is related to the commoner bile acids, but contains eight carbon atoms in the side chain like cholesterol, whereas the usual bile acids contain only five. This has considerable bearing on the view that the bile acids arise from the degradation of cholesterol, and it has been suggested² that the shark, which belongs to a primitive order of fish, lacks the ability to effect more extensive oxidation of cholesterol to the bile acids. This is evidently not entirely true, for Ota⁴ has recently isolated cholic acid as well as scymnol from the bile of a species of shark found in Japanese waters.