High fish oil diet increases oxidative stress potential in mammary gland of spontaneously hypertensive rats.
1. The purpose of this study was to determine whether high omega-3 (19% menhaden oil, 1% corn oil) or high omega-6 (20% corn oil) fatty acid diets would decrease expression of hypertension in the female spontaneously hypertensive rat (SHR), promote tumourigenesis in the rat 7,12-dimethylbenz[a]anthracene (DMBA) model of mammary cancer or increase the susceptibility of the mammary gland to lipid peroxidation. A group of rats on a 5% corn oil diet served as the low fat control group. 2. We found that the high omega-3 and high omega-6 fatty acid diets did not significantly decrease mean arterial pressure. Marked differences occurred between the effects of omega-3 and omega-6 high fatty acid diets on baseline oxidation, auto-oxidation and iron-ascorbate catalyzed oxidation. The omega-3 diet showed 675% increase in basal oxidation, a 2624% increase in auto-oxidation and a 4244% increase in iron-ascorbate catalyzed oxidation compared to the omega-6 diet in mammary tissue homogenates. Although all rats were given 5 mg DMBA (i.g.), no mammary tumours were observed in any of the dietary groups. 3. We conclude that: (i) high polyunsaturated fatty acid diets do not decrease blood pressure in the female SHR; (ii) high fish oil diet markedly increases oxidative potential in the mammary gland; and (iii) the female SHR is resistant to DMBA-induced tumourigenesis.
Mehta
R S
RS
Department of Pharmacology and Toxicology, College of Pharmacy, University of Georgia, Athens 30605-2356.
Gunnett
C A
CA
Harris
S R
SR
Bunce
O R
OR
Hartle
D K
DK
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004032:Diet; D005227:Fatty Acids / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D005395:Fish Oils / Q000378:metabolism / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced; D015227:Lipid Peroxidation / Q000187:drug effects; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism*; D015674:Mammary Neoplasms, Animal / Q000139:chemically induced; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D011918:Rats, Inbred SHR
D005227:Fatty Acids; D005395:Fish Oils; D015127:9,10-Dimethyl-1,2-benzanthracene