Studies on lipid synthesis by incorporation of super(14)C-acetate during experimental maturation of silver eels, Anquilla anquilla

Migrating silver eels (Anguilla anguilla ) were matured with HCG and salmon pituitary extracts. At successive stages during their sexual development super(14)C-acetate was injected. Synthesis of lipids was studied in the gonads, livers and gills. Sexually immature and spent males show evident similarities in their gonad metabolism. Gonad lipid metabolism is apparently independent of liver metabolism in the males, in contrast to the females, where oocyte development also seems to involve phospholipid and sterol synthesis in the liver. The fatty acids of the neutral lipid fraction of egg yolk are synthesized predominantly in situ in the female gonads. This also applies to a further esterification into triglycerides and sterol esters. In contrast to what is known from other fishes, we have not been able to show the synthesis of wax alcohols and esters in the ovaries. Male gills synthesize predominantly wax esters, while the female gills also show a synthesis of free sterols which seems related to their maturation.