Effects of administration routes on the uptake of uridine and 5-fluorouridine into an adenocarcinoma transplanted to rat liver.

In a model of secondary liver cancer in Wistar rats, the effect of different administration routes on the uptake of 3H-uridine into tumor and several normal tissues was studied. The rats were inoculated with a tumor cell suspension in the central liver lobe. Ten days later, they were distributed into four groups with a catheter placed in the gastroduodenal artery, the portal vein, one of the femoral veins, or in the peritoneal cavity. 3H-uridine was injected 46 h later and after an additional 90 minutes the animals were anesthetised and pieces of liver tumor and normal tissues were removed and frozen. The incorporation into the acid-soluble fraction and RNA was analyzed. In a separate experiment, 3H-fluorouridine was administered by the gastroduodenal artery and a comparison was made with the uptake of 3H-uridine. A significantly higher amount of uridine was incorporated into the tumor by the arterial route. The intraportal and intraperitoneal routes were comparable, while a somewhat higher incorporation was found by the systemic route. The consequences of using the different routes upon the incorporation into RNA of tumor and dose-limiting organs are demonstrated. With the aid of this experimental model, it is possible to evaluate further the effect by different manipulations on different drugs regarding the administration route.