[Cholesterol in the brain of cartilaginous and bony fish]

Data are presented on the content of cholesterol in the brain of 23 fish species with different phylogenetic position and ecology. Stable and lower cholesterol content (mean level 10.6 mg/g wet tissue) in the brain of 11 species of Chondrichtyes was shown together with variable and higher (mean level 13 mg/g wet tissue) one in the brain of 12 species of Teleostei. The data obtained are discussed in relation to phylogenetic position of the species investigated and ecological factors (depth and temperature). The ratio of cholesterol to phospholipids in the brain of fishes is lower than that in mammals.