III. RESULTS: RATS 



Mammary Gland: Adenocarcinomas in female 

 rats occurred with a significant negative trend; 

 none occurred in the high dose group (Table 18). 



Eye: Cataracts and retinal degeneration were 



observed at increased incidences in high dose 

 male and low dose female rats (cataracts--male: 

 control, 1/4; low dose, 0/6; high dose, 14/22; fe- 

 male: 0/1; lfi/19; 2/6; retinal degeneration- 

 male: 2/4; 0/6, 17/22; female: 0/1; 17/19; 3/6). 



TABLE 18. MAMMARY GI.ANU LESIONS IN FEMALE RATS IN THE TWO YEAR FEED STUDY OF 



NITROFURANTOIN 



Control 



600 ppm 



1,300 ppm 



Hyperplasia, Cystic or Lobular 



Overall Rale.s 



Adenocarcinoma (a) 

 Overall Rates 

 Adjusted Rates 

 Terminal Rates 

 Day Dt'Kirst Ohservation 

 Life Tal)le Tests 

 Logistic Regre.ssion Tests 



(a) Historical incidence of adeiKjinasor adenocarcinomas(combined)at study laboratory (mean ± SDi: 17/439(4% ± 3%); 

 historical incidence in NTP studies: 64/1,984(3% ± 3%) 



Nitrofurantoin, NTP TR 341 



48 



