The biosynthesis of squalene and cholesterol from acetate-1-14C has been studied in the homogenate supernatant of carp hepatopancreas, rainbow trout liver and mouse liver. The incubation was carried out with the addition of ATP, NAD, NADP and NADPH at 30℃ for certain periods of time under aerobic and anaerobic conditions.
It was shown that the incorporation of acetate-l-14C into the total lipids was very active in the preparation of rainbow trout liver, less active in carp hepatopancreas, and low in mouse liver. In the fish preparation represented by carp and rainbow trout, the de novo synthesis of the fatty acids exceeds of the sterols. On the contrary, the cholesterogenesis surpasses the lipogenesis in the mouse liver preparation.
In general, the coenzyme requirements for the cholesterol synthesis in the fish are not markedly different from those needed by land animals.
As one of the cofactors required for the cyclization of squalene to lanosterol, the molecular oxygen is very important as shown in the case of aerobic condition. Moreover, it was discussed why certain deep sea sharks contain extraordinarily high amounts of squalene and little cholesterol in their liver oils.