Studies on the metabolism of some chemical species of radio-ruthenium in the rat, 1

The whole body retention of three chemical species of 106Ru was studied in rats. Three ruthenium species were ruthenium chloro complex (Ru-chloro), nitrosyl ruthenium nitrato complex (RuNO-nitrato) and nitrosyl ruthenium nitro complex (RuNO-nitro). When the compounds were administered orally, RuNO-nitro complex showed the highest retention, while RuNO-nitrato and Ru-chloro complexes demonstrated a comparablly low retention. The cumulative urinary excretion for three days of RuNO-nitro complex was the highest. The excretion of RuNO-nitrato was slightly but significantly higher than that of Ru-chloro complex. When the compounds were injected intravenously, the whole body retention of Ru-chloro complex was the highest, followed by RuNO-nitrato and RuNO-nitro in this order. These results suggest (1) that RuNO-nitro complex was absorbed more readily through gastrointestinal wall to the body than RuNO-nitrato and Ru-chloro and (2) that RuNO-nitro and -nitrato complexes in the body were metabolized and excreted faster than Ru-chloro complex.