TABLE 8. 



ABSOLUTE AND RELATIVE LIVER WEIGHTS OF RATS IN THE THIRTEEN-WEEK FEED 

 STUDIES OF NITROFURANTOIN (a) 



Concentration 

 (ppm) 



Number of 



Animals 



Necropsy 

 Body Weight 



(grams) 



Liver Weight 

 (mg) 



Liver Weight/Necropsy 

 Body Weight 



(mg/g) 



MALE 





 600 



1,300 



2,500 



5,000 



10,000 



FEMALE 







600 



1.300 



2,500 



5,000 



10,000 



(a) Mean ± standard error; P values vs. the controls by Dunnett's test (Dunnett. 1955) 



(b)P<0.01 



(c)P<0.05 



TWO YEAR STUDIES 



Body Weights, Feed Consumption, and 

 Clinical Signs 



Mean body weights of high dose male rats were 

 6%-9% lower than those of the controls from 

 week 1 to week 11 and thereafter were within 

 5% of the control weights (Table 9 and Figure 3). 

 Mean body weights of dosed female rats were 



within 6% of those of the controls throughout the 

 studies The average daily feed consumption per 

 rat by low dose and high dose rats was 99% and 

 95% that by controls for males (Table Gl) and 

 101% and 98% for females (Table G2) The 

 average amount of nitrofurantoin consumed per 

 day was estimated to be 60 and 110 mg/kg for 

 low and high dose male rats and 30 and 60 

 mg/kg for low and high dose female rats. Dosed 

 rats had bright yellow urine. 



Nitrofurantoin, NTP TR 341 



38 



