Antioxidant defense mechanisms in the male rat: interaction with alcohol, copper, and type of dietary carbohydrate

Impaired stimulation of intestinal glucose absorption by portal insulin via hepatoenteral nerves in chronically ethanol-intoxicated rats

In the isolated, jointly perfused small intestine and liver of rats insulin, infused into the portal vein, induced an increase in intestinal glucose absorption via hepatoenteral cholinergic nerves. The possible loss of function of these nerves due to ethanol-induced neuropathy was investigated with 6 weeks ethanol-fed rats. Portal insulin or arterial carbachol failed to increase intestinal glucose absorption but cAMP still did so. The intact stimulatory effect of cAMP indicated an undisturbed capacity of the enterocytes. The loss of action of portal insulin and of arterial carbachol can be explained by the impairment of the hepatoenteral nerves in line with an ethanol-induced neuropathy.

Long-term consumption of red wine does not modify intestinal absorption or status of zinc and copper in rats

Red wines contain many components such as polyphenols and ethanol that may influence mineral absorption. We report on studies in a rat model that were designed to investigate the extent to which short- and long-term intake of red wine or ethanol may influence (67)Zn and (65)Cu absorption in rats. Rats (n = 96) were divided into three groups, a control group that received demineralized water, a group that received red wine diluted with water (v/v) and an ethanol group that received 6% ethanol. Half of each group was used for the short-term study; the others were used for the long-term study. After 3 d (short-term study) or 28 d (long-term study) of beverage consumption, the rats were gavaged with 2 mL of solution containing 2027 nmol (67)Zn and 902 nmol (65)Cu. Subsequently, 3-d urinary and fecal collections were performed and analyzed for total and isotopic Zn and Cu. In the long-term study, blood, tibia and liver were also sampled for mineral status assessment. Neither short- nor long-term intake of red wine altered (67)Zn or (65)Cu absorption. In contrast, long-term (but not short-term) ethanol consumption significantly increased both (67)Zn and (65)Cu absorption compared with the control and red wine groups. The long-term consumption of ethanol or red wine did not affect blood or tissue Zn or Cu levels. In conclusion, short- or long-term consumption of red wine did not have a negative effect on intestinal absorption or tissue levels of zinc and Cu in rats.

Oxidative stress associated with exercise, psychological stress and life-style factors

Oxidative stress is a cellular or physiological condition of elevated concentrations of reactive oxygen species that cause molecular damage to vital structures and functions. Several factors influence the susceptibility to oxidative stress by affecting the antioxidant status or free oxygen radical generation. Here, we review the effect of alcohol, air pollution, cigarette smoke, diet, exercise, non-ionizing radiation (UV and microwaves) and psychological stress on the development of oxidative stress. Regular exercise and carbohydrate-rich diets seem to increase the resistance against oxidative stress. Air pollution, alcohol, cigarette smoke, non-ionizing radiation and psychological stress seem to increase oxidative stress. Alcohol in lower doses may act as an antioxidant on low density lipoproteins and thereby have an anti-atherosclerotic property.

Antioxidant defense mechanisms in the female rat: interactions with alcohol, copper, and type of dietary carbohydrate

The purpose of this study was to examine the effects of ethanol, type of dietary carbohydrate (fructose vs. starch), and levels of dietary copper (deficient vs. adequate) on antioxidant defense mechanism in the female rat. The consumption of 20% ethanol in the drinking water depressed growth rate due to a reduction of feed efficiency. Ethanol also lowered hepatic copper concentration, but had no effect on hepatic iron. Among the three antioxidant enzymes studied [i.e., superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase], only catalase activity was increased by ethanol. This effect was independent of copper or the type of dietary carbohydrate. As expected, copper deficiency dramatically reduced SOD. Copper deficiency also reduced GSH-Px activity; however, the combination of fructose feeding with copper deficiency caused a further reduction in GSH-Px. The data show that copper deficiency, per se, and the combination of copper deficiency with fructose feeding lower the antioxidant defense system in female rats.