Application in Physiological and Metabolic Studies

The position of labelling must be chosen in such a way that the products of metabolism can be identified, e.g. by labelling with T or C in the side chain of an aromatic compound if the fate of the side chain is of interest, or labelling in the aromatic part of the molecule if this is the main object of investigation. Double labelling, for instance by T and C at different positions, is often very helpful. 

New drugs developed in laboratories of the pharmaceutical industry must be investigated with respect to their metabolism, before they are admitted for general use. Labelling of the drugs with radionuclides at certain positions of the molecule is the most appropriate method for detailed examination of the metabolism. 

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