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Biomedical subjects

J J Ghosh

Publications and source records attributed to J J Ghosh.

At least 55 records · Page 3Linked to original sources
PubMed1977

Hepatic induction of threonine dehydratase and tryptophan pyrrolase to tyrotoxic rats.

The levels of hepatic threonine dehydratase and tryptophan pyrrolase are elevated in 5% tyrosine-fed rats, and these increases are dependent on the dietary tyrosine level. Experiments with RNA and protein synthesis inhibitors indicate that the appearance of these new enzyme activities are dependent on concomitant new protein synthesis and the inducer operates at a transcriptional level.

Animals↗
PubMed1977

Mescaline-induced changes of brain-cortex ribosomes. Mescaline demethylase activity of brain-cortex soluble supernatant.

Brain-cortex slices demethylate mescaline and p-methoxyacetanilide, a reference O-demethylating substrate, though the rate of demethylation of mescaline is about one third that of the reference substrate. The demethylase activity is localized mostly in the soluble supernatant (105 000 x g). It is purified 47-fold with respect to the demethylation of mescaline by ammonium sulfate precipitation and DEAE cellulose chromatography. The partially purified demethylase, which is stable for 3-5 days at -5 degrees C in the presence of dithiothreitol and glutathione and is inhibited by p-chloromercuribenzoate, has maximal activity at pH between 7.2 and 8.0. It demethylates mescaline into 3,4-dimethoxy-5-hydroxyphenethylamine and 3,5-dimethoxy-4-hydroxyphenethylamine and some unidentified derivatives.

Acetamides↗
PubMed1977

Effect of dietary threonine supplementation on tyrosine toxicity in the rat.

The objective of this study was to determine the effect of threonine supplementation on tyrosine metabolism in rats fed a low protein diet with excess tyrosine. The growth retardation and the development of eye and paw lesions that occur in rats ingesting a basal plus 3% or 5% L-tyrosine diet could be alleviated partially by the addition of 0.5% or 1.0% L-threonine to the diet. An increased blood tyrosine level in rats fed excess tyrosine was also lowered by threonine supplementation. In tyrotoxic conditions, the activities of liver tyrosine transaminase (EC 2.6.1.5) and threonine dehydratase (EC 4.2.9.16) were elevated, but p-hydroxyphenyl pyruvic acid oxidase (EC 1.13.11.27) which is also intimately associated with tyrosine toxicity was found to be inactivated. Furthermore, biosynthesis of ascorbic acid in liver was significantly lowered in this condition. However, addition of L-threonine in the diet, not only could cure the signs developed due to excess tyrosine, but also could affect the levels of enzymes studied.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed1977

Binding of mescaline with subcellular fractions upon incubation of brain cortex slices with [14C] mescaline.

Incubation of brain cortex slices in the presence of glucose resulted in the permeation of about 65% of [14C] mescaline into slices. Of this, about one-third radioactivity was bound with nuclei, mitochondria, microsomes, and ribosomes. Dialysis of subcellular fractions did not markedly reduce the amounts of radioactivity bound to the fractions. The permeation into slices and the binding of mescaline to subcellular fractions were fairly time-dependent, but were inhibited by the presence of potassium cyanide, or by the absence of glucose and by heating to 80 degrees C for 1 min.

Animals↗