[Basic and salvage pathways of NAD biosynthesis in organs of normal rats, tumor-bearing rats and in tumors].

The rates of quinolinic and nicotinic acids and nicotinamide utilization for NAD biosynthesis in organs of normal rats and those with lymphosarcoma of Pliss and Walker's carcinosarcoma were studied. All three compounds were shown to be NAD's precursors in the liver and kidneys of normal animals. Quinolinic acid failed to stimulate the increase in NAD concentration in the liver of Walker carcinosarcoma-bearing rats. An insignificant rise in NAD concentration was registered in the liver of rats with lymphosarcoma of Pliss following quinolinic acid treatment. The rates of nicotinic acid and nicotinamide utilization in the liver of tumor-bearing animals were lower than in healthy controls. Quinolinic acid utilization was the most intense in the kidney of rats with Walker's carcinosarcoma while nicotinic acid and nicotinamide were mostly utilized in the kidney of rats with lymphosarcoma of Pliss. None of the three precursors caused NAD concentration to rise in Walker's carcinosarcoma cells whereas nicotinamide injection was followed by an increase in NAD concentration in Pliss lymphosarcoma cells. To summarize, the neoplastic cells under study do not use the basic pathway of NAD biosynthesis and are characterized by different rates of nicotinic acid and nicotinamide utilization.