[Recording protein metabolism and cell proliferation with the stable isotope 15N]

Investigations of nitrogen and protein metabolism with the stable isotope 15N were carried out on 11 patients with atherosclerosis and 7 healthy control subjects. After oral application of 3 g 15NH4Cl (95 At% 15N) per 70 kg body weight the incorporation of the isotope 15N in plasma proteins and blood cells and the 15N elimination in urine were followed up. Retardations of 15N elimination, an accelerated incorporation of 15N in fibrin and a retarded 15N incorporation in platelet protein were observed in patients with atherosclerosis. The described method enables complex assertions about protein metabolism of the whole body and so represents a possibility to evaluate objectively the influence of an intervention on metabolism.