The effect of dietary vitamin E and beta-carotene on oxidation processes in the rat testis
1991
Lomnitski, L. | Bergman, M. | Schon, I. | Grossman, S.
The effects of dietary vitamin E and beta-carotene were studied on enzymes involved in arachidonic acid metabolism and other related enzymes in the rat testis. Groups of rat were fed various soybean oil-based semi purified diets. Group I was fed a vitamin E-supplemented diet (+ E- beta), Group 2 was fed a beta-carotene-supplemented diet (- E + beta); Group 3, the control group (- E - beta) was fed a vitamin E-deficient diet, and Group 4, the standard diet group (S), was fed vitamin E plus beta-carotene-standard diet. Soybean oxidized oil was added to the three diet groups - (+ E - beta), (- E + beta) and (- E - beta), whereas the diet S group contained non-oxadized oil. After 8 weeks rats were killed, blood and testis samples were collected for biochemical determinations. Vitamin E deficiency caused significant increase in testis thiobarbituric acid value and activities of testis NADPH oxidase, testis 15-lipoxygenase and in plasma pyruvate kinase. In contrast, significant decreases were observed in activity of testis prostaglandin synthetase, compared with antioxidant-supplemented diet groups. We also found a significant increase in 15-lipoxygenase activity, in (- E + beta) diet group, compared with (- E - beta) diet group. Fatty acid analysis of testis parenchyma indicated decrease in palmitate (16:0) and arachidonate (20:4(n - 6)), and increase in oleate (18:1 (n - 6)) linoleate (18: 2(n - 6)) and linolenate (18:3(n - 3)), when compared (- E - beta) diet group with vitamin E-supplemented diet groups. The results suggest that dietary vitamin E has a role in both enzymatic and non-enzymatic peroxidation of polyunsaturated fatty acids in the testis.
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