title: Myelinogenic cycle and myelination status of the brain of the catfish, Heteropneustes fossilis.
abstract: The lipid composition of the brain of the catfish, Heteropneustes fossilis (Bloch) was studied over the age period of 2-12 months, during which time the body weight increased from 2.5 to 33 g. The brain weight increased from 28 to 84 mg between 2 and 9 months of age, with a further increase of only 7 mg during the following three months. The concentration of cholesterol increased slowly up to 5 months of age, from which time the concentration began to increase rapidly and attained adult values at 8 months. The concentration of total lipid-P increased steadily up to the age of 7 months and remained almost constant thereafter. In contrast, there was very little increase in the concentration of the galactolipids (cerebroside + sulphatide) until month 5, after which the concentration increased rapidly to reach the adult level at 8 months of age. The concentration of cholesterol esters decreased during development; however, there occurred a transient rise at 5 months of age, which continued up to 8 months. These data indicate that the period between months 5 and 8 is one of active myelination in the brain of this species. The mole ratio of cholesterol, phospholipids, and galactolipids in the adult fish brain was 31:53:1, much higher than that in adult mammalian brain. Moreover, within the phospholipids, ethanolamine phosphoglyceride comprised < 10%, as against the corresponding value in the mammals of about 40%. These data therefore suggest a low level of myelination in the brain of catfish, as compared to that in higher species.
authors.affiliation: Department of Biochemistry, University of Dhaka, Dhaka-2, Bangladesh.
authors.forename: H K
authors.initials: HK
authors.lastname: Yusuf
authors.forename: M S
authors.initials: MS
authors.lastname: Islam