Subcellular distribution of taurine and cysteinesulphinate decarboxylase in developing rat brain

The concentration of taurine and the activities of cysteinesulphinate decarboxylase and glutamate decarboxylase have been measured in rat brain. During development, taurine exhibited a decrease in concentration unrelated to the activity of cysteinesulphinate decarboxylase which increased during the same period. The distribution of taurine in subcellular fractions of adult and 7-day-old rat brain was typical of most amino acids, whereas half of the cysteinesulphinate decarboxylase activity was found in the nerve-ending cytoplasm. In anatomical distribution, taurine displayed great regional heterogeneity but both cysteinesulphinate decarboxylase and glutamate decarboxylase were more evenly distributed. Hypertaurinaemia was shown to have no effect on the entry of glycine into the brain or on its utilization in protein synthesis.

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Effect of phenylalanine on protein synthesis in the developing rat brain

Biochemical Journal ◽

10.1042/bj1170325 ◽

1970 ◽

Vol 117 (2) ◽

pp. 325-331 ◽

Cited By ~ 75

Author(s):

H. C. Agrawal ◽

A. H. Bone ◽

A. N. Davison

Keyword(s):

Amino Acids ◽

Rat Brain ◽

Free Amino ◽

Myelin Proteins ◽

Free Amino Acid Pool ◽

Adult Rat ◽

Adult Rat Brain ◽

Old Rats ◽

Developing Rat ◽

The Brain

1. Inhibition of the rate of incorporation of [35S]methionine into protein by phenylalanine was more effective in 18-day-old than in 8-day-old or adult rat brain. 2. Among the subcellular fractions incorporation of [35S]methionine into myelin proteins was most inhibited in 18-day-old rat brain. 3. Transport of [35S]methionine and [14C]leucine into the brain acid-soluble pool was significantly decreased in 18-day-old rats by phenylalanine (2mg/g body wt.). The decrease of the two amino acids in the acid-soluble pool equalled the inhibition of their rate of incorporation into the protein. 4. Under identical conditions, entry of [14C]glycine into the brain acid-soluble pool and incorporation into protein and uptake of [14C]acetate into lipid was not affected by phenylalanine. 5. It is proposed that decreased myelin synthesis seen in hyperphenylalaninaemia or phenylketonuria may be due to alteration of the free amino acid pool in the brain during the vulnerable period of brain development. Amyelination may be one of many causes of mental retardation seen in phenylketonuria.

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Regulation of tubulin by triiodothyronine in hypothyroid rat brain

Bioscience Reports ◽

10.1007/bf01116995 ◽

1985 ◽

Vol 5 (8) ◽

pp. 643-648 ◽

Cited By ~ 2

Author(s):

Anjana Mazumder ◽

Kamal Das ◽

Pranab K. Sarkar

Keyword(s):

Protein Synthesis ◽

Rat Brain ◽

Brain Maturation ◽

Normal Brain ◽

Neonatal Brain ◽

Organ Cultures ◽

Postnatal Brain ◽

Enhanced Sensitivity ◽

Brain Exposure ◽

Developing Rat

The effect of T3 (triiodothyronine) on the induction of tubulin in hypothyroid developing rat brain has been examined using organ cultures of brains from late fetal, neonatal and postnatalrats. The neonatal brain displayed maximum sensitivity to T3. Hypothyroidism resulted in a 26% decline in the level of tubulin in the neonatal brain as opposed to a 5–15% decline in the fetal or postnatal brain. Exposure of the hypothyroi d neonatal brain to T3 for 2 h in culture led to a 61% rise in the level of tubulin in contrast to a 41% increase seen in the case of normal brain. Total protein synthesis was not significantly affected. The preferential decline of tubulin in the neonatal hypothyroid brain, its enhanced sensitivity to T3 compared to normal brain, and the coincidence of the period of sensitivity to that of brain maturation indicate that the regulation of the level of tubulin by T3 in the developing brain is a natural ontogenic phenomenon.

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