Effects of low copper and high zinc intakes and related changes in Cu,Zn-superoxide dismutase activity on DMBA-induced mammary tumorigenesis.
The effect of low copper and high zinc intakes on Cu,Zn-superoxide dismutase (Cu,Zn-SOD) activity and mammary tumorigenesis induced by 9,10-dimethyl-1,2-benzanthracene (DMBA) was investigated. Groups of 40 weanling female Sprague-Dawley rats were fed a modified AIN-76 diet containing the following (/kg diet): 1 mg Cu (0.016 mmol) and 30 mg Zn (0.459 mmol); 6 mg Cu (0.094 mmol) and 30 mg Zn (0.459 mmol) (control); or 6 mg Cu (0.094 mmol) and 150 mg Zn (2.295 mmol) for 21 wk. At 5 wk, 30 rats/group were given 4 mg (15.6 mumol) DMBA in corn oil intragastrically, and controls (10/group) received corn oil alone. Erythrocyte Cu,Zn-SOD activity was measured at 3, 5 (just before DMBA), 9, 13, 17, and 21 wk. The group fed the high-Zn diet had a slightly lower weight gain and food consumption. DMBA treatment had no effect on these parameters. Plasma and liver Cu concentration decreased in the low-Cu group. Femur zinc was significantly elevated in the high-Zn group. Erythrocyte Cu,Zn-SOD activity was decreased in the low-Cu group from 3 to 21 wk and was significantly elevated in the high-Zn group at 3 and 5 wk. In the low-Cu group, there were 5 nonmalignant adenomas and 3 malignant adenocarcinomas; in the control group, there were 4 adenomas and 3 adenocarcinomas; in the high-Zn group, there were 5 adenomas and 3 adenocarcinomas. No relationship between Cu,Zn-SOD activity and the presence of tumors could be found.
Fischer
P W
PW
Food Directorate, Health and Welfare Canada, Ottawa, Ontario.
Campbell
J S
JS
Giroux
A
A
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003300:Copper / Q000494:pharmacology*; D004032:Diet; D004435:Eating / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology; D005260:Female; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D013054:Spectrophotometry, Atomic; D013482:Superoxide Dismutase / Q000378:metabolism*; D015032:Zinc / Q000494:pharmacology*
D015127:9,10-Dimethyl-1,2-benzanthracene; D003300:Copper; D013482:Superoxide Dismutase; D015032:Zinc