Dietary (n-3) Fatty Acids Affect Rat Heart, Liver and Aorta Protective Enzyme Activities and Lipid Peroxidation

Abstract

In a 16-wk study, weanling Wistar rats (32 males and 32 females) were fed a modified AIN-76 diet containing 20% fat with various (n-3) fatty acids. All dietary fats provided the same amount of saturates, monounsaturates, and total essential fatty acids [(n-6) + (n-3)]. The control diet contained lard/corn oil (L/CO). The other diets contained (n-3) fatty acids from linseed oil (LSO), from linseed oil + menhaden oil (LSO + MO) or from menhaden oil (MO). The (n-3) diets reduced total and HDL-cholesterol, particularly in rats fed the MO diet. Platelet thromboxane levels were equally depressed by the LSO and MO diets. Dietary (n-3) fatty acids significantly elevated docosahexaenoic acid in livers and hearts of male and female rats, with females reaching higher levels. This increase was accompanied by reduced arachidonic acid, except for hearts of females in which the major decrease was in linoleic acid. Overall, enzyme activities in the MO-fed group were decreased to the following levels (relative to the activity in the control group): heart Mn superoxide dismutase (SOD), 28%; liver CuZnSOD, 82%; aorta CuZnSOD, 32%. Greater reductions in these enzyme activities were seen in the female rats fed the MO diet compared with male rats. Lipid peroxidation, assessed by urinary, heart and liver thiobarbituric acid reactants, was increased by dietary (n-3) fatty acids (MO greater than LSO + MO greater than LSO greater than L/CO) and was higher in females than in males. These results indicate that enhanced lipid peroxidation occurs with the increased oxidative stress of elevated tissue (n-3) fatty acids accompanied by reduced SOD activity.

Effects of Octreotide on Liver Metastasis and Intrametastatic Lipid Peroxidation in Experimental Pancreatic Cancer

“…The assumption that high doses of ALA/LA enhance oxidative stress is supported by several authors [33, 34, 35]. Furthermore, the hypothesis that carcinogenesis is increased by elevated lipid peroxidation is supported by Bartsch et al [28]who reported that free radical damage and DNA alkylation are involved in carcinogenesis induced by nitrosamines.…”

Influence of Octreotide and Tamoxifen on Tumor Growth and Liver Metastasis in N-Nitrosobis(2-oxopropyl)amine-Induced Pancreatic Cancer in Syrian Hamsters

“…Furthermore, the same pathomechanism is discussed for nitrosamine-induced carcinogenesis in pancreatic cancer. Since octreotide decreased liver metastases, the influence of octreotide on oxidative stress should be analyzed in further trials [26, 27, 28, 29]. …”

Mechanism for obesity-induced increase in myocardial lipid peroxidation

“…At least four general potential mechanisms could contribute to the obesity-related myocardial lipid peroxidation: (a) increased myocardial work and subsequent radical production via mitochondrial respiration; 4 (b) decreased myocardial antioxidant defense; 12 ± 14 (c) increased fat deposition within myocardial tissue; 15,16 andaor (d) increased rates of radical formation such as superoxide (O 2 À ) or the hydroxyl radical. 17 Theoretically, it is possible that all of these mechanisms are present and participate in the increase in myocardial lipid peroxidation in obesity.…”