Regulation of tubulin by triiodothyronine in hypothyroid rat brain

1985 ◽  
Vol 5 (8) ◽  
pp. 643-648 ◽  
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.

Quantitative Measurements of Regional Glucose Utilization and Rate of Valine Incorporation into Proteins by Double-Tracer Autoradiography in the Rat Brain Tumor Model

1989 ◽  
Vol 9 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Michihiro Kirikae ◽  
Mirko Diksic ◽  
Y. Lucas Yamamoto
Keyword(s):  
Protein Synthesis ◽  
Brain Tumor ◽  
Rat Brain ◽  
Brain Tissue ◽  
Glucose Utilization ◽  
Tumor Model ◽  
Normal Brain ◽  
Normal Brain Tissue ◽  
Rat Brain Tumor ◽  
Brain Tumor Model

We examined the rate of glucose utilization and the rate of valine incorporation into proteins using 2-[18F]fluoro-2-deoxyglucose and L-[1-14C]-valine in a rat brain tumor model by quantitative double-tracer autoradiography. We found that in the implanted tumor the rate of valine incorporation into proteins was about 22 times and the rate of glucose utilization was about 1.5 times that in the contralateral cortex. (In the ipsilateral cortex, the tumor had a profound effect on glucose utilization but no effect on the rate of valine incorporation into proteins.) Our findings suggest that it is more useful to measure protein synthesis than glucose utilization to assess the effectiveness of antitumor agents and their toxicity to normal brain tissue. We compared two methods to estimate the rate of valine incorporation: “kinetic” (quantitation done using an operational equation and the average brain rate coefficients) and “washed slices” (unbound labeled valine removed by washing brain slices in 10% thrichloroacetic acid). The results were the same using either method. It would seem that the kinetic method can thus be used for quantitative measurement of protein synthesis in brain tumors and normal brain tissue using [11C]-valine with positron emission tomography.

scholarly journals Activation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in homogenates of developing rat brain

1979 ◽  
Vol 182 (2) ◽  
pp. 367-370 ◽  
Author(s):  
W A Maltese ◽  
J J Volpe
Keyword(s):  
Rat Brain ◽  
Cholesterol Synthesis ◽  
Specific Activity ◽  
Postnatal Period ◽  
Developing Brain ◽  
Brain Maturation ◽  
Assay Mixture ◽  
Coa Reductase ◽  
Developing Rat ◽  
Homogenization Medium

The specific activity of 3-hydroxy-3-methylglutaryl-CoA reductase increases when homogenates of developing rat brain are incubated at 37 degrees C or kept on ice. This increase is completely blocked by the addition of F- to the homogenization medium and the assay mixture. The capacity for activation of the reductase is greatest during the early postnatal period and declines as brain maturation proceeds. The data suggest that catalytic modification of the reductase may play a role in the regulation of cholesterol synthesis in the developing brain.

Effect of neonatal hypothyroidism on maturation of nuclear triiodothyronine (T3) receptors in developing rat brain

1980 ◽  
Vol 95 (4) ◽  
pp. 495-499 ◽  
Author(s):  
Kazumasa Ishiguro ◽  
Yukichi Suzuki ◽  
Tamotu Sato
Keyword(s):  
Rat Brain ◽  
Binding Capacity ◽  
Physiological Role ◽  
Brain Maturation ◽  
Control Group ◽  
High Concentration ◽  
Neonatal Hypothyroidism ◽  
Developing Rat ◽  
T3 Receptors

Abstract. Changes of nuclear T3 receptors during brain maturation were studied in normal and hypothyroid rats. In normal rats, the higher receptor concentration present in the neonatal period (0.35 ± 0.04 ng T3/mg DNA) decreased at the age of 14 days (0.25 ± 0.02 ng T3/mg DNA), and remained at this level thereafter to 35 days of age (0.25 ± 0.03 T3/mg DNA). In contrast, hypothyroid rats showed a significantly higher concentration than that found in an age-matched control group at the age of 14 days (0.38 ± 0.07 ng T3/mg DNA), and maintained this level up to 35 days of age (0.37 ± 0.03 T3/mg DNA). The binding affinity was similar in both groups and throughout maturation (mean ± sd in normal groups: 1.9 ± 0.3 × 1010m−1, in hypothyroid groups: 1.7 ± 0.2 × 1010m−1). Plasma T3 concentrations showed changes reciprocal to those in the binding capacity of T3 receptors. These results indicate that nuclear T3 receptors in rat brain mature by the age of 14 days, in association with a decrease in binding capacity, and this process seems to be T3-dependent. The physiological role of the high concentration of T3 receptors observed in neonatal and hypothyroid rat brain during development is at present not clear.

Mitochondrial DNA, RNA, and protein synthesis in different regions of developing rat brain

1979 ◽  
Vol 4 (1) ◽  
pp. 37-52 ◽  
Author(s):  
A. M. Giuffrida ◽  
M. N. Gadaleta ◽  
I. Serra ◽  
M. Renis ◽  
E. Geremia ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Protein Synthesis ◽  
Rat Brain ◽  
Rna And Protein Synthesis ◽  
Developing Rat

scholarly journals Subcellular distribution of taurine and cysteinesulphinate decarboxylase in developing rat brain

1971 ◽  
Vol 122 (5) ◽  
pp. 759-763 ◽  
Author(s):  
H. C. Agrawal ◽  
A. N. Davison ◽  
L. K. Kaczmarek
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Rat Brain ◽  
Nerve Ending ◽  
Glutamate Decarboxylase ◽  
Decarboxylase Activity ◽  
Regional Heterogeneity ◽  
Anatomical Distribution ◽  
Developing Rat ◽  
The 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.

Utilization of tyrosine and tryptophan for protein synthesis by undernourished developing rat brain

1983 ◽  
Vol 8 (11) ◽  
pp. 1471-1480 ◽  
Author(s):  
S. Kalyanasundaram ◽  
P. S. V. Ramanamurthy
Keyword(s):  
Protein Synthesis ◽  
Rat Brain ◽  
Developing Rat
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