SOME INVESTIGATIONS USING C-14-LABELED COMPOUNDS INTO THE DESIGN OF RADIOPHARMACEUTICALS SUITABLE FOR THE EVALUATION OF MYOCARDIAL-METABOLISM

The rate of metabolism of 14C-labelled lactate, pyruvate, acetoacetate and acetate was examined in fed and starved mice as a guide to whether the labelling of any of these substrates with 11C would produce a useful radiopharmaceutical for evaluating myocardial metabolism. All the substrates were rapidly metabolised with up to 60% of the injected activity being expired as 14CO2 within 30 minutes of administration. The rate of loss of 14CO2 decreased as the labelled carbon became more remote from the 1-C position. It was concluded that labelling these substrates with 11C would not produce a useful radiopharmaceutical unless the 11C position was remote from the 1-C group. © 1979.