Tumorigenicity test of N-(5-Nitro-2-furfurylidene)-1-aminohydantoin by dietary administration in BDF1 mice.

The carcinogenicity of N-( 5-Nitro-2-furfurylidene )-1-aminohydan to in (nitrofurantoin, NF-153) was examined in (C57BL/6N x DBA/2N)F1 (BDF1) mice. Three hundred of mice were divided into three groups, each group consisting about 50 male and 50 female mice. Nitrofurantoin was given in powdered diet at dose levels of 0. 3, 0. 075, or 0 % to the respestive group of mice. The overall incidence of tumors in male and female mice was as follows: 0. 3% NF group, 7. 7 and 25. 9%; 0. 075% NF group, 1. 9 and 16. 7 % ; in the control group, 22. 6 and 29. 6 %, respectively. In the male, the total incidence of tumors in two experimental groups and that of hepatic adenoma in 0. 3% NF group was significantly decreased from that of control by p and noncarcinogenic nitrofuran in rats4> that is detoxified relatively slowly compared to the other noncarcinogenic one, such as 5-nitro-2-furoic acid. However, NF-153 has been used clinically for more than 25 years with no reports on the human neoplasias etiologically attributable to this drug9>. The present study was undertaken to clarify the tumorigenicity of NF -153 in mice. Animals. Male and female (C57BL/6N x DBA/2N)F1 (BDF1) mice 4 weeks old were obtained from Charles River Japan Inc. They were divided into 3 groups of about 50 males and 50 females each and housed 5-6 in plastic polycarbonate cases. They were maintained at 24±2°C and moderate humidity at 55±5%. Administration of NF. NF-153 was mixed with powdered diet CE-2 (Clea Japan, Inc.) at concentrations of 0. 075 and 0. 3%. Control mice were fed with the powdered diet CE-2. The powdered feed and water were supplied ad libitum. Administration of the test chemical was started when the mice were 9 weeks old. Pathological Studies. All of the mice were observed once daily and weighed once a month,