The Benefits of Administering Folic Acid in Order to Combat the Oxidative Damage Caused by Binge Drinking in Adolescent Rats

AIMS

An important mechanism in alcohol-induced injury is biomolecular oxidative damage. Folic acid is supplied to chronic alcoholic patients in order to prevent this situation, as this is the main vitamin deficiency that they suffer from. Acute alcohol exposure, such as binge drinking, is one of the most widespread ethanol consumption models practiced by adolescents. However, there is no evidence of folic acid body profiles after this pattern of consumption.

METHODS

Four groups of adolescent rats were used: control, alcohol (exposed to intraperitoneal binge drinking), control folic acid-supplemented group and alcohol folic acid-supplemented group. Folic acid levels, protein, lipid and DNA oxidative damage in serum, and liver glutathione (GSH) and reduced/oxidized glutathione ratio (GSH/GSSG) were measured.

RESULTS

Binge-drinking rats had higher lipids and DNA oxidation levels. They also had lower hepatic GSH levels and GSH/GSSG ratio. Folic acid supplementation to binge-drinking rats does not change the serum protein oxidation but decreases lipid and DNA oxidation. Finally, GSH increased to control levels with folic acid supplementation.

CONCLUSION

Folic acid supplementation is an economic and efficient therapy against the oxidative damage in lipids and mainly in DNA stability caused by binge drinking during adolescence. It has also been demonstrated that folic acid increases GSH levels, improving the antioxidant status and revealing a hepatoprotective effect during binge drinking.

Effect of dietary selenite on development and intestinal absorption in offspring rats

AIM

The present study aims to compare selenium (Se) status in offspring rats born to selenium-deficient and selenium supplemented dams and to analyse Se's influence on intestinal parameters and the intestinal absorption of selenomethionine (Se-Met).

MAIN METHODS

Male and female Wistar rats (150-200 g) were randomised in: control (C) (0.1 ppm Se), Se-deficient (SD) (0.01 ppm Se) and Se-supplemented (SS) (0.5 ppm Se) groups; and were mated to obtain their offspring. Se levels in serum, urine and faeces in offspring and in mothers' milk were measured by graphite-furnace atomic absorption spectrometry. Duodenal transport studies in offspring were performed using an in vivo perfusion of different Se-Met concentrations (2, 5, 10, 25, 75 and 150 μM).

KEY FINDING

A Se-deficient diet provoked a decrease in the offspring's body weight and intestinal parameters, while the supplemented diet increased these values. Serum Se levels were similar between Se-deficient and control offspring because the urinary excretion of Se was smaller to compensate for Se homeostasis. Intestinal Se-Met absorption obeys the Michaelis-Menten equation with lower apparent constant (K(m)) and maximal velocity (V(max)) in the SD group. However, the C and SS groups presented similar K(m) and different V(max). The V(max) showed greater values in the following order of rank: SS>C>SD groups.

SIGNIFICANCE

Selenium intake deficiencies in offspring lead to the development of compensatory mechanisms in order to normalise serum selenium levels. These mechanisms, however, do not permit normal body development; nor do they regulate intestinal parameters and Se-Met transport.

Selenium or selenium plus folic acid intake improves the detrimental effects of ethanol on pups' selenium balance

The levels of folic acid and selenium, two nutrients with antioxidant properties, decrease in dams exposed to ethanol during gestation and lactation. This decrease affects their antioxidant balance, and consequently the health of their offspring. In this study we have proved that a supplemented diet with Se (0.5 ppm) or with Se (0.5 ppm) plus folic acid (8 ppm) to ethanol-exposed (20%v/v) dams prevents the ethanol-provoked effects in their offspring's Se deposits. Se levels in milk, serum, urine, faeces and several tissues were measured by graphite-furnace atomic absorption spectrometry. Results show that ethanol decreases Se deposits in pups' heart, liver, kidney and testes. However Se levels in pancreas and in serum were increased by ethanol; it also compromised the weight and the length of the offspring at the end of lactation. Our supplemented diets to ethanol dams increased all of these impaired levels, and restored Se pancreas concentration to a control status. However Se-only therapy mainly displaces Se to serum, kidney and spleen, and co-treatment with Se plus folic acid, mainly displaces Se to liver and brain. This data demonstrate that the qualitative and quantitative Se organ deposits depend on ethanol consumption, Se status, and the presence of other antioxidants.

Dietary selenium plus folic acid as an antioxidant therapy for ethanol-exposed pups

BACKGROUND

Nutrients such as folic acid and selenium are decreased in dams exposed to ethanol during gestation and lactation, affecting their metabolism, antioxidant balance, and the future health of their progeny. We will study whether the supplementation of the maternal diet with folate and selenium can prevent ethanol-induced oxidative liver disorders in the offspring.

METHODS

Dams were randomised into four groups: control, alcohol, alcohol+folic acid+Se, and control+folic acid+Se. We determined selenium by graphite-furnace atomic absorption and antioxidant enzyme activities, lipid peroxidation, and protein carbonyl by spectrophotometry in the offspring.

RESULTS

Alcohol increased serum Se levels and glutathione peroxidase (GPx) activity. However, in the liver of pups from ethanol-exposed dams a decrease in selenium was provoked and GPx activity increased with the double supplementation. Glutathione reductase (GR) and catalase (CAT) activities increased with ethanol, while double supplementation significantly decreased the GR activity. The supplemented diet reduced the protein peroxidation found in ethanol pups.

CONCLUSIONS

These results suggest that folic acid+Se could be effective in neutralising the damage of ethanol consumption in pups since it prevents peroxidation protein products.

Selenium tissue distribution changes after ethanol exposure during gestation and lactation: selenite as a therapy

Ethanol consumption affects maternal nutrition and antioxidant status together with the future health of their progeny. Selenium (Se) is a trace element with antioxidant activity; we will study the effect of ethanol in dams on Se bioavailability, antioxidant balance and gestational parameters. We also will study if a Se-supplemented diet (0.5 ppm) administered to ethanol-exposed dams avoids the undesirable effects provoked by ethanol. We have used four experimental groups: control (C); chronic ethanol (A); control+Se (CS) and chronic ethanol+Se (AS). Se levels in serum, urine, faeces, and several tissues were measured by graphite-furnace atomic absorption spectrometry. Serum glutathione peroxidase (GPx) activity was determined by spectrometry. Se bioavailability is altered by ethanol, causing a decrease in Se retention, reducing Se levels in cortex, muscle, mammary gland and salivary gland while elevating Se values in heart, liver and spleen. On the other hand, Se supplementation increases some of these parameters. Serum GPx activity was decreased by ethanol, while a Se-supplemented diet restores these values to those found in controls. We have demonstrated that ethanol decreased Se retention in dams, affecting their tissues' Se deposits, decreasing GPx activity in serum, gestational parameters and the weight of their progeny. Selenite supplementation counteracts these decreasing effects, except in cortex.

Effect of maternal ethanol consumption during pregnancy and lactation on kinetic parameters of folic acid intestinal transport in suckling rats

Ethanol ingestion is known to interfere with folate absorption and metabolism. A fostering/crossfostering analysis of maternal ethanol exposure effects on jejunum and ileum kinetic parameters in vivo of offspring rat folic acid absorption at 21 days postpartum was carried out. The rats were divided into four groups: CP, control pups; GP, pups exposed to ethanol only during gestation; LP, pups exposed to ethanol only during lactation; GLP, pups exposed to ethanol during gestation and lactation. Jejunal and ileal loop transport studies were performed using in vivo perfusion at a flow rate of 3 ml/min for 5 min. Folic acid concentrations of 0.25, 0.5, 1, 1.5 and 2.5 microM: were used. Jejunal and ileal absorption values were determined by the difference between the initial and the final amounts of substrate in the perfusate and expressed as picomoles per square centimeter of intestinal surface every 5 min. The results indicated that ethanol consumption by the dams during gestation and/or lactation led to significant changes in V(max), with no significant changes in apparent K(m). These findings suggest that exposure to ethanol during gestational and suckling periods leads to a general delay in postnatal body weight and that intestinal folate absorption appears to be upregulated in suckling rats, this effect being higher in the LP group.

Response of the exocrine pancreas to the CCK on offspring rats of ethanol dams. Effects of folic acid

AIMS

The aim of this study was to study the reverse effect of folic acid administered during gestation and lactation to ethanol-treated dams, on cholecystokinin Cholecystokinin (CCK) stimulus-secretion coupling in pancreatic exocrine secretion in offspring rats.

METHODS

Animals were randomized into three groups: Control group (C) received water and basic diet during pregnancy and lactation period; ethanol-treated rats (E) received ethanol and basic diet; the ethanol+folic acid group (EF) received folic acid supplement concomitantly with ethanol administration.

RESULTS

Body and pancreatic weight was lower in offsprings after ethanol treatment. Folic acid supplementation increased these parameters with respect to ethanol rats. After CCK stimulation, a significant decrease in amylase, lipase and chymotrypsin activities in the duodenal juice were detected in ethanol, this trend was partially corrected with folate supplementation.

CONCLUSION

Ethanol exerts its action on exocrine pancreatic secretion by two pathways: 'per se' and diminishing the folic acid content, because a folic acid supplement in rats during pregnancy and lactation periods produces an advantageous effect on amylase, lipase and chymotrypsin secretion in their offspring. Although extrapolation from animal studies may be tenuous, the present findings may explain the use of folic acid in the prevention of ethanol-induced damage by increasing the enzyme levels to adequate physiological concentrations.

Effects of prenatal or postnatal ethanol consumption on zinc intestinal absorption and excretion in rats

AIMS

The effect of ethanol consumption, either during the pregnancy or lactation period, on the altered metabolism of zinc is not well-defined; consequently, this study was performed to analyze the effect of chronic ethanol exposure on milk consumption, serum, milk, duodenal absorption, fecal and urinary excretion of zinc in dams and offspring during either gestation or lactation in the rat. A complementary study was performed regarding pregnancy outcome. We evaluated testosterone values, the offspring born/litter and several indices such as fertility, viable gestations and the survival index.

METHODS

To study the effect of chronic alcoholism during gestation or lactation separately, at birth control newborns were cross-fostered to ethanol dams (ED), and the offspring issued from the ethanol treated mothers were cross-fostered to control dams (CD). Thus, three experimental groups of offspring were formed: (i) control offspring receiving no treatment (CO); (ii) offspring exposed to ethanol only during gestation (GO); and (iii) offspring exposed to ethanol only during lactation (LO). All the results were compared with offspring pair-fed groups (PFO) born of the pair-fed dams (PFD).

RESULTS

Duodenal absorption of zinc increased significantly in LO offspring when the substrate concentrations in the perfusion medium were 25, 75, and 150 microM. A higher faecal excretion in GO pups compared with those with LO exposure and control groups (CO and PFO). The urine excretion of zinc was higher for LO offspring with respect to the other three experimental groups (CO, GO, and PFO).

CONCLUSIONS

Maternal adaptation resulted in zinc retention, adequate to meet the demands of pup's growth in the face of a lower diet intake. The zinc status in pups is regulated by a higher absorption of zinc and intestinal conservation of endogenous fecal zinc after postnatal ethanol consumption. The increase in urinary zinc excretion could be responsible for decreased serum zinc. However, we found an increase in serum zinc probably due to an increase in the zinc absorption values.

Gender difference in the pancreatic trypsinogen response to ethanol withdrawal in rat pups

This study was designed to examine the effects of ethanol withdrawal on offspring rats that consumed ethanol during gestation and lactation, in order to examine whether there was an improvement in pancreatic trypsinogen and lipase activities at 2 months postpartum with respect to offspring that fed on ethanol until death. A second purpose for our study was to determine if a folic acid supplement during gestation and lactation was sufficient or insufficient to reverse the negative effects of ethanol consumption. Both genders were used with the aim of investigating any differential pancreatic behaviour. The animals were randomized into five groups: the control group (CG) received water and a basic rat diet during pregnancy, lactation and growth; the ethanol group (EG) was fed an ethanol diet during pregnancy, the suckling period and growth until death; the ethanol-water group's (E+WG) ethanol was eliminated after lactation; The ethanol-folic acid group (E+FG) received a folic acid supplemented diet during pregnancy and the suckling period and in the ethanol+folic acid group (E+FG+FG) this supplementation continued during growth. Our results showed that ethanol administration or ethanol withdrawal did not significantly alter lipase activity in the pancreas. Ethanol administration decreased trypsinogen levels in the pancreas of males and females. However, in males, as opposed to females, the withdrawal of ethanol did not recover the values of pancreatic trypsinogen content, nor did a folic acid supplementation significantly alter the parameters we studied. Our treatment produced no effect on lipase levels. There was a gender-related difference in pancreatic trypsinogen content, the implication being that in future all results on exocrine pancreas function in male and female animals should be analysed separately.

Effects of maternal ethanol consumption during pregnancy or lactation on intestinal absorption of folic acid in suckling rats

A fostering/crossfostering analysis of the effects of maternal ethanol exposure on jejunal and ileal folate absorption was performed. Male and female rats were randomized into two groups. In the first group, ethanol-treated rats received ad libitum 5, 10 and 15% ethanol in the drinking fluid during three successive weeks. A consumption of 20% was maintained in this group for 5 additional weeks. Ethanol-treated rats were mated. Group 2 served as the control. To study the effect of chronic alcoholism during lactation or gestation separately, at birth (2nd day postpartum) control newborns were cross-fostered to ethanol dams (EG), and the pups issued from the ethanol treated mothers were cross-fostered to control dams (CG). Thus, three experimental groups of pups were formed: (1) control pups receiving no treatment during gestation and lactation (CG); (2) pups exposed to ethanol only during gestation (GG); and (3) pups exposed to ethanol only during lactation (LG). At 21 days postpartum the jejunal and distal ileum folate absorption was determined in the offspring rats by a perfusion technique. Milk folic acid levels were determined by an immunoluminometric assay. The results showed an increase in jejunal folic acid absorption in offsprings exposed to ethanol only during the lactation period (LG). However, in pups exposed to ethanol only during the gestation period (GG), the jejunal folic acid absorption was significantly increased only at concentrations of 0.25, 0.5 and 2.5 microM. No free folic acid absorption occurred in the distal ileum of control pups (CG) at day 21 at all assayed concentrations but in offsprings exposed to ethanol only during the gestation or lactation periods absorption did take place. Pups exposed to ethanol during the gestation period (GG) showed decreased values in ileum folic acid absorption at the lowest assayed concentration (0.25 microM) compared to values obtained for pups exposed to ethanol only during lactation (LG). Milk folic acid levels were significantly decreased in the ethanol-fed dams on day 21 of lactation. These results indicate that exposure of rats to ethanol during the lactation period affects more severely postnatal development of intestinal functions than ethanol exposure only during gestation. In summary, both the exposure to ethanol itself and the decrease in folic acid intake caused alterations in the function of the intestinal mucosa in the offspring, which in turn altered absorption time and development. However, the present results do not explain how ethanol stimulated intestinal absorption of folic acid in pups exposed to ethanol during the gestation or lactation periods. Further studies are needed.

Effect of prenatal exposure to ethanol on hepatic elongation factor-2 and proteome in 21 d old rats: protective effect of folic acid

In this article, we study the effects of ethanol intake during pregnancy and lactation on hepatic and pancreatic elongation factor-2 (EF-2) of 21 d old progeny. At the same time, the effect of ethanol on the level of other relevant hepatic proteins was determined using proteomic analysis. The results show that ethanol not only produces a general increase of protein oxidation, but also produces an important depletion of EF-2 and several other proteins. Among the hepatic proteins affected by ethanol, the concomitant supplementation with folic acid to alcoholic mother rats prevented EF-2, RhoGDI-1, ER-60 protease, and gelsolin depletion. This protective effect of folic acid may be related to its antioxidant properties and suggests that this vitamin may be useful in minimizing the effect of ethanol in the uterus and lactation exposure of the progeny.

Brown and white adipose tissue lipid composition in three successive progenies of rats: effects of ethanol exposure

The effect of ethanol exposure on the fatty acid composition of brown and white adipose tissue in three successive rat progenies at the end of an experimental period (24 weeks) was studied. Ethanol-treated rats received a standard rat chow diet and 5, 10 and 15% ethanol in the ad libitum drinking fluid over 3 successive weeks. Then a concentration of 20% ethanol was maintained for 5 additional weeks up to the end of the experimental period. The males and females in the ethanol treated group were mated to obtain the 1st generation of offspring. Then female and male rats from the 1st generation were mated to obtain the 2nd generation. Finally, males and females from the 2nd generation were mated to obtain the 3rd generation of ethanol treated rats. Another group served as control and received only water and a standard rat chow diet. The control group was handled in the same way as the other experimental groups. In the 1st and 2nd generations the percentage of stearic acid (18:0) decreased and palmitoleic (16:1n7) and oleic acid (18:1n9) increased in both adipose tissues of ethanol-treated rats with respect to control. Additionally, n-3 and n-6 series were reduced both in brown and white adipose tissues. In the 3rd generation the fatty acid composition of the white adipose tissue was similar to that of control rats. Thus, no significant difference in essential fatty acids and oleic acid (18:1n9) were found. However, the fatty acid composition of the brown adipose tissue, in the 3rd generation, was similar to that observed in the 1st and 2nd generation. Thus, a decrease in essential fatty acids and an increase in oleic acid (18:1n9) was found. This suggests adaptation to ethanol consumption during successive progenies in white adipose tissue. However, in brown adipose tissue the values indicate a triglyceride storing during the thermogenesis, which is more important to newborns.

Protective effect of folic acid against oxidative stress produced in 21-day postpartum rats by maternal-ethanol chronic consumption during pregnancy and lactation period

In this paper we show the protective effect of folic acid on oxidative stress in offspring caused by chronic maternal ethanol consumption during pregnancy and the lactation period. Glutathione reductase (GR) specific activity was assayed in liver and pancreas of offspring and mothers. In the offspring, these tissues were also assayed for markers of oxidative damage to lipids and proteins. The results show that ethanol exposure during pregnancy and lactation increased the specific activity of GR in tissues of the mothers (32-34% increase) as well as in the liver of their progeny (24%). Thiobarbituric acid reactive substances (TBARS) were also increased in the liver and pancreas of 21-day-old rats (37- and 54%, respectively). Alcohol also increased the amount of carbonyl groups in proteins in both tissues. These measures of ethanol-mediated oxidative stress were mitigated when pregnant rats were treated with folic acid concomitantly to ethanol administration. The antioxidant capacity of folic acid seems to be involved in its protective effect. The results obtained in the present work suggest that folic acid may be useful in the prevention of damage and promotion of health of the progeny of ethanol-treated rats.

Intestinal absorption and enterohepatic circulation of folic acid: effect of ethanol

This study sought to determine the intestinal in vivo absorption of folic acid by the whole intestine, and the appearance of this compound in bile in control and ethanol-fed rats. Intestinal folic acid absorption in rats with the bile duct cannulated decreased in ethanol-fed rats with respect to control rats. This difference was significant at 1 and 2.5 microM concentrations of folic acid. This result is in contrast with previous work in our laboratory on rats with intact bile ducts, where ethanol-fed rats had an increase in folic acid absorption. The results obtained in the present work suggest an impaired enterohepatic recycling of folic acid in ethanol-fed rats.

Effects of folic acid and amino acids supplementation on zinc intestinal absorption in the progeny of ethanol-treated rats

This study was designed to examine the effects of supplementation with folic acid and amino acids in dams that consumed ethanol during gestation and lactation to see whether there is an improvement in the intestinal absorption of zinc in pup rats on the 21st day after birth. The rats were randomized into two groups: Ethanol-rats (EG) were administered ethanol during the pregnancy and lactation periods; the ethanol-folic acid group (EFG) received a folic acid and amino acid supplement concomitantly with ethanol administration during pregnancy and lactation. The dams were mated to obtain the first offspring. Two sets of experiments were performed on the offspring at 21 days after birth. In general, in the first set, jejunal zinc absorption in the offspring of EG and EFG groups showed a gradual increase along with increased perfusion time at all assayed concentrations. Jejunal zinc absorption expressed as nmol/intestinal surface was higher in the ethanol-folic acid group than in ethanol animals at all assayed concentrations except at 25 microM concentration. In the second set of experiments, distal ileum zinc absorption in the offspring of ethanolfolic acid dams showed a significant increase at all concentrations tested. These results indicate that supplementation of folic acid and amino acids to dams that consume ethanol during gestation and lactation increase serum and milk zinc levels, although the zinc ingestion is lower. In pups of the supplemented dams, the jejunal and ileal absorption of zinc increased; as a consequence, the serum zinc levels increased. The activity of alcohol dehydrogenase, a metaloenzyme dependent on zinc levels, also increased.

Intestinal absorption and biliary secretion of 5MTHF: effect of ethanol

The aim of this work was to study intestinal absorption, using the whole intestine in vivo with 5-methyltetrahydrofolate (5MTHF), and the subsequent appearance of this compound in the bile, in control and in ethanol-fed rats. The ethanol-fed rats drank ethanol (5 to 30% vol/vol) in tap water for 5 wk. A consumption of 30% was maintained in this group for 20 additional weeks. The two groups of rats were cannulated at the beginning and at the end of the intestine. Three solutions containing 0.5, 1.0, and 2.5 microM of cold 5MTHF and 14C-methyltetrahydrofolic acid (0.01 microCi/mL) in each were perfused throughout the intestine at a flow rate of 4.5 mL/min. The absorption of folate was calculated from the difference between concentrations at the beginning and at the end of the perfusion. A decrease in 5MTHF uptake was observed at the concentration of 1.0 microM (p<0.05): however, folate absorption was not significantly modified at 0.5 and 2.5 microM in the perfusate. Serum folate levels were significantly lower in the ethanol-fed rat group. This fact could be due to a lower intake of folate in the diet and/or to the effect of alcohol on the intestinal absorption. The bile duct was isolated and cannulated with a polyethylene cathether. No significant differences were noted in the biliary folates between the control and the ethanol-fed rats.

Folic acid intestinal absorption in newborn rats at 21 day postpartum: effects of maternal ethanol consumption

This study was designed to examine the effects of prenatal and postnatal exposure of ethanol in the in vivo absorption of free folic acid in the small intestine in pups rats at the 21st day after birth. The rats were accustomed to increasing amounts of ethanol (5 to 20%, vol/vol) in tap water for 1 month. During pregnancy and suckling period, ethanol-fed dams were assigned again to ethanol 20% in drinking water. Two sets of experiments were performed. In the first set, jejunal free folic acid absorption in control group and litters nursed by dams receiving ethanol showed a gradual increase along with the increase of perfusion time at all the assayed concentrations. In general, in litters of ethanol-fed dams, jejunal free folic acid absorption expressed as nmol/intestinal surface, nmol/g tissue wet weight and nmol/g tissue dry weight were higher than in control animals. In the second set of experiments, in distal ileum loops, free folic acid absorption did not occur in control pups, but appeared in litters exposed to ethanol. Milk folic acid levels are significantly decreased in ethanol-treated dams. However, only a slight decrease in the serum folic acid levels occurs in litters of ethanol-fed dams. In conclusion, the results obtained in the present work suggested a different pattern of free folic acid absorption in distal ileum for the two groups. The exposure of rats to ethanol during the pregnancy and suckling period, can affect postnatal development of intestinal functions and could play a role in the genesis of malnutrition observed in the infant.

Zinc intestinal absorption in newborn rats at 21 day postpartum: effects of maternal ethanol consumption

This study was designed to examine the effects of prenatal and postnatal exposure of ethanol in the in vivo absorption of zinc in the small intestine in newborn rats at the 21st day after birth. The rats were accustomed to increasing amounts of ethanol (5 to 20%, vol/vol) in tap water for 1 month. During pregnancy and suckling period, ethanol-fed dams were assigned again to ethanol 20% in drinking water. Two sets of experiments were performed. In the first set, jejunal zinc absorption in control group and litters nursed by dams receiving ethanol showed a gradual increase along with the increase of perfusion time at all the assayed concentrations. In general, in litters of ethanol-fed dams, jejunal zinc absorption expressed as nmol/intestinal surface was higher than in control animals. In the second set of experiments, distal ileum zinc absorption in offspring of ethanol-fed dams showed a significantly decrease at all concentrations tested. The results showed that intestinal parameters measured in jejunum and distal ileum of litters exposed to ethanol were always significantly less than in control newborn. These results indicate that exposure of rats to ethanol during the pregnancy and suckling period, may affect postnatal development of intestinal functions and decrease the distal ileum zinc absorption in pups at the end of the lactation period.

Chronic alcoholism decreases polyunsaturated fatty acid levels in human plasma, erythrocytes, and platelets--influence of chronic liver disease

The effect of chronic ethanol ingestion on fatty acid composition of plasma, erythrocyte and platelet phospholipids and on plasma 6-keto-PGF1alpha was studied. Two groups of alcoholic subjects, one of them with chronic liver disease, were studied and compared to a control group of healthy subjects. Linoleic acid was not affected by alcoholism but its larger metabolites arachidonic acid (20:4n6) and docosatetraenoic acid (22:4n6) tended to be lower in erythrocytes and platelets of both groups of alcoholic patients; the decrease was more marked in the presence of chronic liver disease. Docosahexaenoic acid (22:6n3) was markedly decreased in plasma, erythrocytes and platelets obtained from alcoholic patients with chronic liver disease. Plasma levels of 6-keto-PGF1alpha, a metabolite of prostacyclin (PGI2), remained unchanged. We conclude that chronic ethanol ingestion induces important changes in long-chain polyunsaturated fatty acids, mainly in platelets, and that these changes are exacerbated when patients suffer from chronic liver disease.

Changes in the ileal disaccharidase activities in rats after long-term ethanol feeding

Brush border enzymatic activities (maltase, lactase and sucrase) have been determined in the ileal mucosa of rats subjected to a 30% ethanol ingestion for 3 and 5 months. The data were compared with the results obtained with control rats. Mucosal protein content after 3 months of ethanol treatment was similar to that of control rats. Maltase, lactase and sucrase specific activities in ileal mucosa were significantly decreased in ethanol-fed animals as compared to control rats. After 5 months of ethanol consumption, the protein content was decreased in ethanol-fed rats. However, no differences were found between specific activities of maltase, lactase and sucrase of ethanol-fed with respect to control rats. It is suggested that prolonged exposure of rats to ethanol results in adaptive responses to the effects of shorter periods of exposure on intestinal mucosal function.

Folate absorption in the caecum of chronic ethanol-fed rats: in vivo studies

This study was designed to determine the intestinal in vivo absorption of folic acid and methyltetrahydrofolate (MTHF) by the caecum surface at different times after 20 weeks of 30% ethanol ingestion. The absorption results were compared to the data of control rats. Chow and fluid consumption and body weight were significantly lower in ethanol-fed rats. The absorption of folic acid and MTHF by the caecum surface (pmol/cm2) was generally decreased in ethanol-fed rats at all concentrations assayed with respect to control animals (except for absorption of 0.5 and 2.5 microM folic acid at 15-min intervals). The results obtained in the present work also suggest a different absorptive behaviour of folic acid and MTHF in the caecum under the influence of chronic alcohol ingestion.

Folate absorption in the jejunum of chronic ethanol-fed rats: in vivo studies

This study sought to determine the intestinal in vivo absorption of folic acid and methyltetrahydrofolate (MTHF) by jejunum surface at different times, after 20 weeks of 30% ethanol ingestion. The absorption results were compared with the data of control rats. In general after ethanol treatment jejunal folic acid absorption was higher than in control rats. When the folic acid concentrations in the perfusion medium were 0.5 microM an increase at later times in ethanol-fed rats was found. At 1 microM the folic acid absorption values were significantly higher at the earlier time. When the concentration assayed was 2.5 microM, significant modifications were only seen at 30 min. Results of MTHF absorption by jejunum of ethanol-fed rats were similar to absorption values of control rats. No significant differences between both groups were found. The results obtained in the present work suggested a different absorptive behavior of both substrates and a different effect of ethanol on folic acid and MTHF absorption in the jejunum.

Changes in the fatty acid profile of plasma and adipose tissue in rats after long-term ethanol feeding

The effect of chronic ethanol feeding on the fatty acid composition of plasma and abdominal adipose tissue in rats was studied. Animals were maintained on a 30% ethanol solution in drinking water for 3 and 5 months. Control rats were given water. Caloric intake was similar in control and ethanol-fed rats at the end of the experimental period. However, a decrease in body weight was observed in rats that had consumed ethanol. Palmitoleic (16:1n7) and oleic (18:1n9) acids increased markedly, and linoleic acid (18:2n6) decreased in the plasma and in the adipose tissue of ethanol-fed rats with respect to control rats. After 3 months of ethanol ingestion, long-chain polyunsaturated fatty acids were reduced both in plasma and adipose tissue. When ethanol was administered for 5 months, only plasma long-chain polyunsaturated fatty acids of the n-3 series were decreased. This suggest that changes induced by ethanol ingestion in essential fatty acid metabolism is less pronounced when ethanol feeding is maintained for a long period of time.

Comparative effects of intestinal absorption of folic acid and methyltetrahydrofolic acid in chronic ethanol-fed rats

This study concerns in vivo folic acid and methyltetrahydrofolic acid (MTHF) absorption by the whole intestinal surface after 20 weeks of 30% ethanol ingestion in drinking water. The results were compared with control rats fed ad libitum. The total intestinal serosal areas were similar in ethanol-fed and control rats. Significant increases in intestinal length, and decreases in tissue wet and dry weights were found in ethanol-fed rats. Serum folic acid concentrations were significantly less in the animals which had ingested ethanol than in the control rats. Intestinal folic acid absorption was significantly increased at lower substrate concentrations (0.5 and 1 microM), while no difference was observed at 2.5 microM in the ethanol-fed rats. Folic acid absorption relative to tissue wet weight showed significant increases at all tested concentrations in the ethanol-fed rats. Intestinal MTHF absorption showed no significant changes at 0.5 microM MTHF concentration, and an increase was observed in the absorption values at 1 and 2.5 microM concentrations in the ethanol-fed rats. When expressed as tissue wet weight, MTHF absorption values in ethanol-fed rats increased at 1 and 2.5 microM but did not differ at 0.5 microM substrate concentrations. The above results indicate compensatory responses in the folic acid and MTHF intestinal absorption after chronic ethanol ingestion. These effects are observed when the whole intestinal surface is evaluated.

The effect of ethanol on intestinal L-leucine absorption in rats

The chronic effect of ethanol on leucine absorption by the whole rat intestine (between duodenum and rectum) was studied using an in vivo multiple-pass perfusion technique. Leucine concentrations in the perfusion medium were 5, 10 and 25 mM respectively in successive passes. Ethanol was administered in drinking water during a one month induction period and then for a four week period of ad libitum ingestion of 30% ethanol solution. The results were compared with ad libitum-fed control rats. The total calorie consumption due to the chow diet plus ethanol increased in the rats which had ingested ethanol when compared with that of the controls. The daily protein intake in ethanol-fed rats was less than that of the controls. No significant differences in morphometric tissue parameters were found between the two experimental groups. Chronic ethanol ingestion provoked a slight (but not significant) decrease in net leucine absorption at 5 mM leucine concentration. In contrast, minor increases in the absorption values were found at 10 and 25 mM leucine concentrations. These findings suggest that the diminished active mechanisms of leucine absorption provoked by ethanol ingestion are compensated for by the enhanced diffusive processes, the passage of the nutrients through the whole intestine, and that the low protein consumption of ethanol-fed rats in ad libitum conditions isn't enough to provoke significant decreases in leucine absorption by the whole intestine.

Effect of chronic ethanol on D-galactose absorption by the rat whole intestinal surface

The in vivo absorption of D-galactose by rat whole intestinal surface after 4 weeks of 30% ethanol ingestion in drinking water has been studied, and the results were compared with ad lib-fed control rats. The total serosal intestinal area was determined by integration obtaining similar values between control and alcohol-treated groups. In the caecum surface of ethanol-fed rats slight but not significant increases were found, while the jejunum area decreased with respect to control rats. Total galactose absorption during 10 min of perfusion was slightly increased in ethanol-fed rats but these results were not significant with the substrate concentrations tested. When absorption data were referred to serosal surface, the absorption/cm2 values in ethanol-fed rats were increased at the studied galactose concentrations although these results were only statistically significant at 10 mM. In conclusion, the present data indicates a slight increase in D-galactose absorptive capacity by the whole intestine in ethanol-fed rats which suggest that the tissue traditionally not evaluated such as caecum and colon could modify the functional response to the absorption nutrients.

Comparative effect of distal and proximal intestinal resection and bypass on the rat exocrine pancreas

We studied the effects of small-bowel resection and bypass on pancreatic function in rats subjected to a 50% distal resection (DR), a 50% proximal resection (PR), a 50% jejunal bypass (BP) or an intestinal transection (SH) (controls). Duodenal contents were collected after cannulation (under basal conditions). Afterwards, an in vivo duodenal perfusion was made using a glucose/saline solution and perfusate was collected for 1 h. Following this, a cholecystokinin (CCK) solution was injected into the jugular vein (1 U/kg body wt.) and perfusion continued for another 1 h. Basal duodenal volume only increased in rats with a PR, and no significant changes occurred in protein content. In basal conditions, no decreases in amylase, lipase, trypsin, or chymotrypsin activities after DR, PR or BP were detected. When animals were subjected to a perfusion and CCK stimulation, no significant changes occurred in animals with BP; the volume was maintained in rats with PR and DR but a decrease in protein and enzymatic contents was found. We concluded that, in basal conditions, the lack (resections) or exclusion (BP) of 50% of the small bowel does not negatively affect the digestive function. When however, a sustained activity is required, the extirpation of intestinal surface provokes a fall in enzymatic activities and is not modified if only the intestinal transit is suppressed, as occurs in the cases of BP.

Changes in lipid parameters after intestinal resection or bypass in the rat

Intestinal resection, bypass and adaptative postoperative mechanisms developed as a consequence of that surgery, are considered good methods for improving knowledge of gastrointestinal physiology as well as possible effects that the intestine could have on the general metabolism. 50% jejunoileal bypass (BP), 50% proximal (PR) and distal (DR) intestinal resections were performed on rats to compare the influence of resected intestinal segments or bypassed loop localization could exert on different serum lipid parameters. One month after surgery significant increases in total serum cholesterol and cholesterol esters were found. There was no change in free cholesterol. A decrease in triglyceride was observed after distal and proximal resection but no changes after bypass. The cholesterol/phospholipid ratio was increased after resection and after bypass. It has been suggested that the changes in lipid metabolism produced after resections and bypass depend mainly on the loss of absorptive surface rather than on the position of the resected segment. The bypass loop may itself still exert some influence on lipoprotein metabolism, mainly on high density lipoprotein-cholesterol.

D-galactose absorption for the whole intestinal surface after different types of resection and bypass

In vivo D-galactose absorption by the whole intestine between duodenum and rectum was studied in rats 1 month after sham operation, 50% proximal resection, intestinal bypass, or 50% distal resection. The total serosal areas were evaluated by means of an integrative method, obtaining reduced surfaces in resected or bypassed animals as compared with controls. The rate of D-galactose absorption, measured within 10 min, increased after proximal resection and bypass and diminished after distal resection, although the level was similar to that of controls at higher substrate concentrations. When expressed as serosal area, results in proximal and bypassed animals were higher than in controls, without differences (at lower galactose concentrations), and increased (at 25 mM), after distal resection. The total absorptive capacity related to wet and dry weight showed no differences in proximal and bypassed groups and a decrease after distal resection. The above results confirm a good level of recuperation when proximal intestinal surface is excluded. In case of ileal extirpation, a smaller compensatory response was found, which would be compensated for by a high substrate concentration in the intestinal lumen.

Leucine absorption after jejunoileal bypass in rats

Jejunal and ileal absorption of L-leucine has been studied in rats subjected to jejunoileal bypass and in sham-operated rats, for five minute periods, using a perfusion technique. Aminoacid concentrations were: 1, 2.5, 5, 10 and 25 mM. In some experiments methionine was added to determine simple diffusion. The ratio of the active/diffusive components of absorption were calculated at the different luminal aminoacid concentrations in both groups of rats, showing that this ratio was lower in control animals.

Disaccharidase activities after jejunoileal bypass in rat

Digestive enzymatic activities (maltase, lactase and sucrase) have been determined in the intestinal mucosa of rats subjected to a jejunoileal bypass of 45 cm. The weight and protein content of the mucosa (mg/cm) were significantly decreased in the bypassed segment and significantly increased in the unbypassed segment, as compared to control rats. Maltase, lactase and sucrase specific (U/g protein) and total activity (U/cm intestine) were significantly decreased in the bypassed jejunum, compared to sham-operated rats. In the ileum, maltase specific and total activities increased in bypassed animals while the lactase and sucrase activities remained unchanged.

Effect of distal enterectomy on cholesterol and bile salt levels in the rat

The effect of 50% or 80% distal enteroctomy on cholesterol and bile salt levels in male Wistar rats have been investigated. Short time measurements showed that serum cholesterol levels were maximal after 20 days from 50% intestinal resection and after 10 days from 80% intestinal resection. This increase was maintained in 50% resected rats 1 and 5 months after operation, whilts in 80% resected group the values became normal. Portal blood and bile cholesterol levels remain almost normal except 5 months after 50% intestinal resection. Bile salt concentration and bile salt output in the bile decrease after 1 and 5 months from 50% intestinal resection and after 1 month from 80% intestinal resection. These results together with data of fecal loss of bile salts indicate that in 50% resected rats new steady states have been reached, with low levels of bile salts in the bile. One month after 80% resection the fecal loss of bile salts was so high that the conversion of cholesterol into bile salts was increased. After 5 months from 80% resection values in serum and bile were almost normal suggesting either an increase in extrahepatic cholesterol synthesis or a partial prevention of fecal loss that can be explained by the observed caecal enlargement.

Galactose transport across rat small intestine in vivo following distal resections of varying extents

The kinetics of D-galactose absorption across rat small intestine in sham, 50 and 80% distal intestinal resected animals, have been studied under in vivo conditions. After 5 months post-resection the total galactose absorption was increased. The relationship between total absorption of substrate and its concentration in the perfusate showed a non-saturable component and a saturable one that can be inhibited by phloridzin, both in control and remnant intestine. The slope of the line that represents the non-saturable component is greater in remnant duodenum and jejunum, indicating that the apparent mass-transfer coefficient, K'D, was increased by distal resection. Non-linear fitting of the saturable component data gave an apparent maximal galactose transport rate (J'max, nmol/cm2 . min) of 134 +/- 13 (sham), 132 +/- 9 (50% resected), 139 +/- 9 (80% resected) in duodenum and of 103 +/- 11 (sham) and 106 +/- 12 in jejunum. Apparent Michaelis constants (K'm, mM) of 12.1 +/- 3.2 (sham), 12.3 +/- 2.2 (50% resected) and 13.3 +/- 2.2 (80% resected) in duodenum and of 11.6 +/- 3.7 (sham) and 12.8 +/- 3.7 (50% resected) in jejunum were found. Correction of the kinetic constants for the unstirred water layer (u.w.l.) effects showed that the differences between 'real' KD's of the experimental groups increased, whereas 'real' Km's did not significantly change. There were no significant differences in duodenal galactose absorption between 50 and 80% resected rats.

[Histophysiologic aspects of the remnant intestine of rats subjected to partial resection of the small intestine]

The effect of small bowel resection on the morphology, mucous secretion and alkaline phosphatase activity of the remnant intestine was studied five months after surgical operation. Distal small bowel resection produced hyperplasia and infiltration of lymphocytes. The intestinal neutral and acid mucosubstances, and the alkaline phosphatase activity were increased in resected animals, whilst the sulphomucins content of goblet cells was unaltered. The serum alkaline phosphatase activity two and five months after resection was also increased.

Amino acid absorption in jejunum of rats in vivo--a kinetic comparison of distal resection effects

Jejunal absorption of leucine and cycloleucine by sham and 50% distal resected rats in vivo was studied by measuring the passive component and the active transport. After 5 months postresection the total amino acid absorption was increased. The mass-transfer coefficients of the passive process (obtained in presence of methionine) were higher in remnant jejunum than that in control rats, whereas the active transport remained unaltered after resection. When the kinetic constants of the saturable and non-saturable components were corrected for the unstirred water layer effects, the "real KD" increased in the resected group, whilst similar values for the "real Km and Jmax" were obtained.

Kinetics of phenylalanine absorption by the rat intestine in vivo after distal resection

The kinetics of L-phenylalanine absorption across rat small intestine in sham and 50% distal resected animals, in vivo, have been studied by perfusing jejunal loops and monitoring the disappearance of the substrate from the perfusate. After 5 months postresection the total phenylalanine absorption was increased. The relationship between total absorption of substrate and its concentration in the bulk phase shows a non-saturable component and a saturable one that can be inhibited by methionine, both in control and remnant jejunum. The slope of the line that represents the non-saturable component is greater in remnant jejunum, indicating that the apparent mass-transfer coefficient, K'D, was increased by distal resection. The kinetic analysis of the saturable component shows that Jmax was unaltered and the apparent semisaturation constant, K'M, was slightly decreased by distal small intestine resection. Correction of the kinetic constant for the unstirred water layer effects shows that the differences between 'real' KD values of the two experimental groups increase whereas 'real' KM values do not change significantly. This indicates that the observed increase in total intestinal absorption in resected animals appears to result from an increase in the intestinal passive permeability.

Effect of intestinal resection in dogs on different digestive parameters

Some aspects of the digestive secretions in intact dogs (Control group) and the same dogs after resections of either 50 or 80% of the small intestine starting from the ileocaecal valve have been studied. In all of the animals the duodenal content flow, duodenal content pH, bile salts and amylase production have been determined; under fasting conditions, response to food (4% fat) and response to cholecystokinin-pancreozymin (CCK-PZ) injection (2 i.u./kg). Our results showed a decrease of pH and amylase production in resected animals, but duodenal content flow and bile salt production were not affected. The increase in duodenal content flow in response to feeding was delayed at onset in resected dogs. The pH and bile salts production were unchanged in response to food and to CCK-PZ injection in all animals, but amylase production decreased in response to food and particularly to CCK-PZ administration in resected animals.

[Protein nutritive utilization in goats with and without exclusion of rumen and reticulum (author's transl)]

The digestive utilization of protein in fistulated goats has been studied through a system of three cannulae. The protein digestibility coefficient is greater with casein in the rumen than with it in the abomasum, explainable by a higher ammonium production. On the other hand, with casein in the abomasum the duodenal digest contains more protein, and aminoacid composition improves in quality and quantity. The differences found in the above mentioned results are mainly due to a rumen bacterial action upon aminoacids and the subsequent absorption of the ammonium formed.

[Influence of small bowel resections on some aspects of digestive secretions in rat (author's transl)]

Some aspects of the digestive secretions both in intact rats (control group) and in rats with resection of 50% and 80% of the small intestine starting from ileocecal valve have been studied. In every animal, the volume of duodenal content, total content of bile salts and amylasic activity have been analysed under the following experimental conditions: fasting, feeding with two diets containing 4% and 20% of fat, and intravenous injections of pancreozymin (2 UI/kg). Total content of bile salts and amylasic activity decrease in resected rats under fasting and feeding. This decrease is greater when larger portions of the intestine are removed. Rats injected with pancreozymin react in a similar way. The amylasic activity decrease in the resected rats indicates a pancreatic hypofunction caused by the resection and cannot be compensated by administration of pancreozymin. Measurements of seric cholesterol show that a 50% resection causes a decrease form normal levels and a 80% resection makes it significant.