Lipid Metabolism in Liver and Brain in Acute Hyperphenylalaninemia in Rats of Different Ages

Abstract

Three phenylalanine injections (1 mg/g body wt) at 4-hour intervals resulted in increases in phenylalanine and tyrosine levels which were age- (4–42 days) and tissue (plasma, brain, liver)-dependent. Incorporation of [1-¹⁴C]-acetate into lipid was constantly reduced by 20–40% in brain but not liver of 7-, 11-, 14- and 21-day-old phenylalanine-injected rats, while in adult brain incorporation was near normal. A similar distribution of label between lipid classes of differing brain regions in injected rats, compared to controls at all ages, indicates a lack of a selective effect on myelin lipid synthesis, suggesting that reduced myelination in hyperphenylalaninemia is not related to high phenylalanine levels per se.

Comparison of α-methylphenylalanine and p-chlorophenylalanine as inducers of chronic hyperphenylalaninaemia in developing rats

“…6), although its activity (Miller et al, 1972;Weber et al, 1970) was reported to be inhibited by high concentrations of phenylalanine. Abnormalities in cerebral lipid composition observed in phenylketonurics (see Menkes, 1967) and hyperphenylalaninaemic rats (Geison & Josephson, 1974) have not yet been studied in a-methylphenylalanine-treated rats.…”