Methodic recommendations for the determination of whole body protein synthesis rates in tracer studies

Abstract

Methodical recommendations are suggested--predominantly for laboratory and small animals (rats and young chickens)--for the determination of parameters of the protein metabolism of the whole body after single doses of a mixture of 15N labelled amino acids by means of the determination of the temporal course of cumulative 15N excretion in urine and the assessment of the tracer kinetic data in a compartment model. These recommendations are to make it possible to carry out purposefully such experiments under comparable conditions. The advantages of this method are: the non-invasive character of the method; the possibility of repeating the experiment with the same animal; the adaptability to other methods of investigation (e.g. measuring energy metabolism); the relatively low expenditure of labour and requirement of test animals; the relatively good reproducibility of the method. Thus this method is a good supplement to the flooding and permanent infusion methods and should be used wherever the determination of parameters of the protein metabolism of the total body is sufficient.