Adrenaline radioactive

The synthesis of pressor amines in the body may convincingly be considered to begin with the essential amino acid, phenylalanine as illustrated in Table I. Gurin and Delluva (86) have reported that phenylalanine labeled with tritium, or containing C14 located both in the carboxyl group and in the position adjacent thereto, was converted in the rat to radioactive adrenaline. Only one C14 atom was present in the side chain and it was in the terminal group bearing the secondary amine (86). However the intermediate steps in the synthesis are by no means so certain, nor does this necessarily preclude other paths of synthesis. 

Gurin, S. and Delluva, A. M., The biological synthesis of radioactive adrenalin from phenylalanine, /. Biol. Chem. 170, 545 (1947). 

After an injection of H-adrenaline, H-metanephrine appears in the urine. The specific activity of this metanephrine, when all the radioactivity has been excreted, is equal to the specific activity of any product of adrenaline which, like metanephrine, is uniquely formed solely from adrenaline. VMA, however, formed from noradrenaline is unlabelled and this lowers the specific activity of VMA compared to that of metanephrine by an amount which is related to the magnitude of this pathway. The proportion of VMA derived from adrenaline is given by the ratio of the specific activity of VMA to the specific activity of metanephrine. 

A radioisotope derivative procedure for the determination of adrenaline and noradrenaline, involving their oxidation to labelled 7-iodoaminochromes with high specific activity has recently been reported [74], The oxidation was carried out with radioactive potassium iodide solution, in the presence of persulphuric acid (Caro s acid) [74],... 

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