Enzyme-altered foci in colons of carcinogen-treated rats.
The distal colon and rectum from male F344 rats treated with 15 mg/kg 1,2-dimethylhydrazine.2HCl (DMH) for 20 weeks were analyzed for focal areas of enzyme alteration. Tissues were embedded in methacrylate at 4 degrees C and cut in 2- to 4-micron serial sections. In DMH-treated rats, 8.8 +/- 2.4 foci/cm2 of examined mucosa were observed at 20 weeks and 7.7 +/- 1.1 foci/cm2 at 31 to 52 weeks, compared with 1.2 +/- 0.6 foci/cm2 in control rats (P = 0.01). The number of foci at 31 to 52 weeks compared with 20 weeks did not change significantly, but the area of altered rectal mucosa increased from 0.22 +/- 0.2% at 20 weeks to 1.47 +/- 0.6% at 31 to 52 weeks (P = 0.051). Most foci had decreased N-acetyl-beta-D-glucosaminidase, alpha-naphthyl butyrate esterase, and mucin in epithelial cells and increased gamma-glutamyl transpeptidase in the stroma. Morphologically, the foci varied from normal to overtly dysplastic. Grossly, tumors were identified in 5 of 20 DMH-treated rats killed at 31 to 52 weeks but not in 12 DMH-treated rats killed at 20 weeks or 30 control rats killed at 20 to 52 weeks. These data suggest but do not establish that enzyme-altered foci are putative preneoplastic lesions in the colon.
Barrow
B J
BJ
Department of Pathology, Case Western Reserve University Medical School, Cleveland, Ohio 44106.
O'Riordan
M A
MA
Stellato
T A
TA
Calkins
B M
BM
Pretlow
T P
TP
D019813:1,2-Dimethylhydrazine; D015720:5'-Nucleotidase / Q000378:metabolism*; D000135:Acid Phosphatase / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D003106:Colon / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D004127:Dimethylhydrazines / Q000633:toxicity*; D006651:Histocytochemistry; D007413:Intestinal Mucosa / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D008297:Male; D008763:Methylhydrazines / Q000633:toxicity*; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D009928:Organ Specificity; D051381:Rats; D011916:Rats, Inbred F344; D012007:Rectum / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism*
D002273:Carcinogens; D004127:Dimethylhydrazines; D008763:Methylhydrazines; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D015720:5'-Nucleotidase; D001619:beta-N-Acetylhexosaminidases; D019813:1,2-Dimethylhydrazine