THE SYNTHESIS OF dl-TRYPTOPHAN-β-C14, INDOLE-3-ACETIC ACID-α-C14, AND dl-TRYPTOPHAN-3-C14

Stimulation of C14-melatonin synthesis from C14-tryptophan by noradrenaline in rat pineal in organ culture.

Previous work has shown that the activity of the melatonin-forming enzyme in the rat pineal gland is elevated in rats kept in continuous darkness as compared to those kept in continuous light. Information about environmental lighting reaches the pineal gland via nerves that liberate noradrenaline. Rat pineal glands in organ culture can form C(14)-melatonin from C(14)-tryptophan as follows: tryp...

Conversion of DL-lactate-2-C14 or -3-C14 or pyruvate-2-C14 to blood glucose in humans: effects of diabetes, insulin, tolbutamide, and glucose load.

Synthesis of liver glycogen from 3-C14-DL-malate: evidence for complete isotopic equilibration of C4-dicarboxylic acids.

There are two known mechanisms of synthesis of phosphopyruvate in animal tissues. One of these is direct phosphorylation of pyruvate by adenosine 5’(pyro)-triphosphate, catalyzed by pyruvate kinase, and the other phosphorylative decarboxylation of oxaloacetate in the presence of inosine triphosphate and phosphoenolpyruvate carboxykinase. Present evidence has been interpreted as suggesting that ...

The conversion of testosterone-3-C14 to C14-estradiol-17beta by human ovarian tissue.

There is a considerable body of biological data linking testosterone and other 19-carbon steroids with the estrogens. Both ovaries and testes may, under certain circumstances, produce androgens and estrogens (14). The administration of testosterone and other androgens to human subjects leads to an increased urinary excretion of estrogenic material (5-lo), which has been identified as estrone, e...

The metabolism of ascorbic acid-1-C14 and oxalic acid-C14 in the rat.

It is known that oxalic acid is a product of ascorbic acid metabolism in the guinea pig (1) and rat (2), and is formed in man from unidentified precursors (3). Oxalates are also of interest because of their occasional toxicity and unexplained deposition. Ascorbic, dehydroascorbic, and 2,3diketogulonic acids are known to give rise to oxalic and threonic acids in approximately quantitative yields...