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Biomedical subjects

S C Cunnane

Publications and source records attributed to S C Cunnane.

At least 109 records · Page 6Linked to original sources
PubMed1988

Vitamin E intake affects serum thromboxane and tissue essential fatty acid composition in the rat.

The influence of dietary vitamin E on the composition of essential fatty acids in rat tissue and plasma lipids as well as serum thromboxane B2 was studied. Diets containing deficient (0 mg/kg diet), adequate (100 mg/kg) or supplemental (1,000 mg/kg) vitamin E were fed to young male rats for 10 weeks. The ratio of dihomo-gamma-linolenic acid to arachidonic acid in phospholipids of plasma, liver, and testes was increased in vitamin-E-supplemented rats. Serum thromboxane B2 was increased in vitamin-E-deficient rats. The data support a role for vitamin E in affecting both metabolism of long chain fatty acids, i.e. dihomo-gamma-linolenic acid, and conversion of arachidonic acid to thromboxane A2.

Animals↗
PubMed1988

Role of zinc in lipid and fatty acid metabolism and in membranes.

This review addresses the role of zinc in the metabolism of lipids including cholesterol, phospholipids, triglyceride, fatty acids, lipoproteins, and essential fatty acids and it discusses to a limited extent the role of zinc in membranes as well as zinc's known effects on receptors. The evidence which is compiled demonstrates two main features of the interactions of zinc in lipid and fatty acid metabolism; 1) that zinc intimately affects many aspects of lipid metabolism through established enzymes but also has modulatory effects whose mechanism is not obvious or established, and 2) many of the observations are superficially contradictory and do not lend themselves to ready explanation. These are the features of a field whose time has come and which beckons further research to clarify these issues.

Animals↗
PubMed1987

Iron intake influences essential fatty acid and lipid composition of rat plasma and erythrocytes.

In view of the clinical importance of iron deficiency as well as the known role of iron in stearic acid desaturation, the effects of higher or lower iron intake on fatty acid composition of blood and liver in the rat were studied. Male Sprague-Dawley rats were fed purified diets that contained iron at 12, 27 or 237 mg/kg. After 12 wk the lipid and fatty acid composition of plasma, erythrocytes and liver was analyzed. Linoleic acid in plasma phospholipids and triacylglycerols was higher, but arachidonic acid was lower in the group fed 12 mg/kg iron than in the groups fed 27 or 237 mg/kg iron. Liver fatty acid and lipid composition was not different between groups. In the group fed 237 mg/kg iron, plasma cholesterol and triacylglycerols were 150%, erythrocyte cholesterol was 137% and erythrocyte phospholipids were 148% of levels in the rats fed 27 mg/kg iron. The fatty acid data suggest a mild impairment in essential fatty acid metabolism in moderately iron-deficient rats. The lipid data suggest a significant alteration in the total lipid content of plasma and erythrocytes of iron-supplemented rats.

Animals↗
PubMed1987

Abnormalities of plasma and erythrocyte essential fatty acid composition in epidermolysis bullosa: influence of treatment with diphenylhydantoin.

The fatty acid composition of plasma and erythrocyte phospholipids was determined in children with various subtypes of epidermolysis bullosa (EB) and in their parents. Patients with recessive dystrophic, dominant dystrophic, simplex, or junctional forms of EB had a higher percentage composition of arachidonic acid in plasma and/or erythrocyte phospholipids compared to age-matched controls. Epidermolysis bullosa patients treated with diphenylhydantoin had lower levels of arachidonic acid in plasma and erythrocyte phospholipids than did untreated EB patients. Parents of children with the recessive dystrophic or junctional EB subtypes had higher linoleic and arachidonic acids in plasma and erythrocyte phospholipids than did controls. Plasma and erythrocyte total lipids were within the normal range in children with EB. Plasma zinc was also normal but plasma copper was elevated in children with recessive dystrophic EB. We conclude that higher arachidonic acid in plasma and erythrocytes may be related to the pathology of EB.

Adult↗
PubMed1987

Hepatic triacylglycerol accumulation induced by ethanol and carbon tetrachloride: interactions with essential fatty acids and prostaglandins.

Triacylglycerol accumulation in the liver (fatty liver) caused by ethanol or carbon tetrachloride involves interactions with essential fatty acids and prostaglandins. The degree to which the fatty liver develops is dependent on total dietary fat intake. Both ethanol and carbon tetrachloride impair desaturation of linoleic acid and dihomo-gamma-linolenic acid and this appears to be relevant to the pathogenesis of fatty liver from two points of view. First, low arachidonic acid in liver phospholipids is associated with increased liver triacylglycerol content whether caused by ethanol, carbon tetrachloride, or essential fatty acid deficiency. Second, essential fatty acids including gamma-linolenic acid and arachidonic acid, as well as the prostaglandins, prevent ethanol- and carbon tetrachloride-induced fatty liver. Arachidonic acid and possibly the prostaglandins are therefore likely to be directly involved in lipoprotein and triacylglycerol secretion by the liver.

8,11,14-Eicosatrienoic Acid↗
PubMed1987

Long-term ethanol consumption in the hamster: effects on tissue lipids, fatty acids and erythrocyte hemolysis.

Male Golden Syrian hamsters at 1 year of age were given a basal diet and either distilled water or 10% absolute ethanol in distilled water to drink for 1 year in order to determine the influence of prolonged ethanol intake on tissue long chain fatty acid, lipid composition and erythrocyte hemolysis in response to osmotic stress. Total lipids were extracted from liver, heart, plasma and erythrocytes. Individual lipid fractions were quantitated and the percentage fatty acid composition of the lipid fractions analyzed by gas-liquid chromatography. Although no significant changes in tissue lipid content or erythrocyte hemolysis were attributable to ethanol intake, fatty acid changes were marked in the ethanol-fed hamsters. The primary fatty acid changes were increased oleic acid (40-50%) and decreased linoleic acid (25-60%) which were observed in all tissues. Arachidonic acid was decreased only in triacylglycerol fractions. The results suggest that in the hamster long-term voluntary ethanol intake alters specific long chain fatty acids, but that erythrocyte membrane integrity and tissue lipid composition were not compromised.

Alcohol Drinking↗
PubMed1986

Dietary manipulation of ethanol preference in the Syrian golden hamster.

Male Golden Syrian hamsters, in which ethanol preference was previously established, were fed a basal diet supplemented with essential fatty acid-rich oils (increased weekly from 10-160 g/kg diet), cholesterol (10 g/kg diet) or retinol palmitate (100 or 200 mg/kg diet), each in an independent study. Within 4-5 weeks, all three supplements were associated with significantly decreased ethanol preference. No consistent change in the fatty acid composition of liver or brain was associated with the decrease in ethanol preference but, in ethanol-fed hamsters, each of the supplements was associated with an increase in total cholesterol and the cholesterol/phospholipid ratio in liver. The essential fatty acid-induced reduction in ethanol preference was not associated with a significant change in blood ethanol elimination rate or time.

Alcohol Drinking↗
PubMed1986

n-3 Essential fatty acids decrease weight gain in genetically obese mice.

1. Lean (ln/ln) and obese (ob/ob) mice were given diets containing a fat source of 100 g evening primrose (Oenothera biennis) oil (fatty acids 18:2n-6, 18:3n-6; EPO) or 100 g cod liver oil (20:5n-3, 22:6n-3; CLO)/kg diet. 2. Weight gain was lower in the ob/ob mice fed on CLO, an effect unrelated to food intake. 3. In the ob/ob mice fed on CLO, thromboxane synthesis by clotting platelets was reduced compared with that in ob/ob mice fed on EPO. 4. The ob/ob CLO-fed mice had lower arachidonic acid but higher levels of n-3 fatty acids in liver, brown adipose tissue and white adipose tissue. 5. The n-3 fatty acids in CLO therefore replaced the n-6 fatty acids in tissue lipids and reduced synthesis of '2 series' prostaglandins in addition to causing lower weight gain in the CLO-fed ob/ob mice.

Animals↗
PubMed1986

Diminished phospholipid incorporation of essential fatty acids in peripheral blood leucocytes from patients with Crohn's disease: correlation with zinc depletion.

Peripheral blood leucocytes from patients with Crohn's disease have been shown to have lower zinc content than those from a normal population. Since zinc influences essential fatty acid metabolism, incorporation of 14C-linoleic and 3H-arachidonic acids was studied in peripheral blood leucocytes from controls and patients with Crohn's disease. The zinc content of the leucocytes was also measured. After incubation for 2 h, content of 3H-arachidonic acid, but not 14C-linoleic acid, was greater in Crohn's disease leucocytes than in controls. In the Crohn's disease leucocytes, incorporation of both labelled fatty acids into the phosphatidylcholine fraction was significantly lower than in controls, whereas the amount of both fatty acids remaining in the leucocytes as free fatty acids was increased by 70%. In Crohn's disease, leucocyte zinc level was positively associated with the percentage of 3H-arachidonic acid incorporation into phosphatidylcholine. We conclude that peripheral blood leucocytes from patients with Crohn's disease have abnormal essential fatty acid metabolism and that 3H-arachidonic acid incorporation into the phosphatidylcholine fraction of leucocyte lipids in Crohn's disease varies as the zinc content of the leucocytes.

Adult↗
PubMed1986

Transient neonatal zinc deficiency.

We report an infant who developed clinical manifestations of zinc deficiency during the first month of life although the diet was adequate for zinc and no other causes could be ascertained. The diagnosis was confirmed by low plasma-zinc concentrations and a positive response to zinc treatment. The fatty acid profile of plasma phospholipids was typical of zinc deficiency (ie, arachidonic acid was markedly decreased). The transient nature of this disorder was evident when no relapse occurred after cessation of zinc therapy and plasma-zinc and arachidonic acid concentrations remained normal. Several explanations for the development of transient neonatal zinc deficiency are offered. The observation demonstrates that occasional infants may have requirements for zinc that are beyond the intakes of the conventional RDA.

Blepharitis↗
PubMed1986

Lipid and fatty acid composition of organs from copper-deficient mice.

Experiments were conducted to study the total lipid and fatty acid composition of liver, kidney, brain and heart of 7-wk-old male C57BL mice. Dietary copper deficiency was initiated at birth by feeding dams a purified diet containing 0.5 mg/kg copper. Offspring were fed the copper-deficient diet 4 wk postweaning. Control dams and offspring were fed the same diet but with added copper in the drinking water, 20 mg/L. Compared with controls the copper-deficient mice exhibited hepatomegaly, cardiac hypertrophy and a 4% reduction in brain weight as well as low ceruloplasmin activity (0.5% of control). Total phospholipid concentration in liver and kidney and total triacylglycerol concentration in kidney was lower in copper-deficient mice compared to concentrations measured in liver and kidney of control mice. The major change in essential fatty acid composition in the copper-deficient mice which was consistent between organs and lipid classes was a significantly lower proportion and absolute amount of dihomo-gamma-linolenic acid. Other changes in fatty acid composition were variable.

Animals↗
PubMed1986

Influence of different dietary fatty acid sources on erythrocyte lipids and plasma and liver essential fatty acids in hamsters fed ethanol.

Hamsters fed ethanol were given three different dietary sources of essential fatty acids; safflower oil, evening primrose oil (both mainly n-6 fatty acids) or linseed oil (mainly n-3 fatty acids). After 7 weeks, plasma, erythrocyte and liver lipids and fatty acids were analyzed. Plasma and liver lipids were not significantly different in the ethanol-fed hamsters compared to the controls. Erythrocyte total phospholipid was increased only in the ethanol-fed groups given n-6 but not n-3 fatty acids. Some fatty acid changes induced by ethanol were predictable, e.g. lower 20:4 n-6 in hamsters fed n-6 fatty acids, but others were not predictable, e.g. higher 22:6 n-3 in all the ethanol-fed groups. The effect of ethanol on hamster lipids and fatty acid composition appears dependent on the predominant class of dietary fatty acids.

Alcohol Drinking↗
PubMed1986

Effect of different dietary proteins on plasma and liver fatty acid compositions in growing rats.

Weanling male rats were fed semipurified diets containing 20% protein derived from casein, soy protein, or wheat gluten for 5 weeks. The fat source was 2% safflower oil (containing 79.4% 18:2n-6). In comparison with the casein-fed rats, the growth rate of rats fed plant proteins was slower, particularly that of rats fed the wheat gluten diet. The plasma cholesterol levels were significantly lower in rats fed wheat gluten than in those fed the other dietary protein regimens. The fatty acid compositions of plasma and liver lipids were also examined. The ratios of 16:1/16:0, 18:1/18:0 and 20:4n-6/18:2n-6 in both plasma and liver phospholipids and cholesteryl esters were consistently reduced in animals fed plant protein suggesting a reduced activity of fatty acid desaturation. The reduction of fatty acid desaturation may possibly be attributed to the low lysine/arginine ratio in plant proteins.

Adipose Tissue↗
PubMed1985

Essential fatty acids in the liver and adipose tissue of genetically obese mice: effect of supplemental linoleic and gamma-linolenic acids.

Genetically obese mice (ob/ob) and their lean litter-mates were given diets iso-energetically supplemented with sucrose, hydrogenated coconut oil, safflower oil or evening primrose (Oenothera biennis) oil. Weight gain over 15 weeks was significantly greater in the evening primrose oil-supplemented obese mice than in the other groups. In all the groups of obese mice, liver total phospholipids contained proportionally less linoleic acid and more dihomo-gamma-linolenic acid and arachidonic acid than did the lean controls. As a percentage of total fatty acids, n-3 essential fatty acids (EFA) in liver and adipose tissue lipids were significantly lower in the obese mice than in the lean controls. Supplementation with EFA-rich oils (safflower and evening primrose oil) increased the proportional composition of n-6 EFA and decreased the n-3 EFA more in the liver total phospholipids of the lean than the obese mice.

Adipose Tissue↗
PubMed1985

Abnormal essential fatty acid composition of tissue lipids in genetically diabetic mice is partially corrected by dietary linoleic and gamma-linolenic acids.

Genetically diabetic mice (db/db) and their non-diabetic litter-mates were maintained for 15 weeks on diets supplemented with safflower oil or evening primrose (Oenothera bienis) oil, both essential fatty acid (EFA)-rich sources, or hydrogenated coconut oil (devoid of EFA). Plasma glucose was higher in the diabetic mice supplemented with the oils than in the unsupplemented diabetic mice. In the oil-supplemented non-diabetic mice, plasma glucose did not differ compared with the unsupplemented non-diabetic mice. The proportional content of arachidonic acid in the phospholipids of the pancreas was significantly decreased in diabetic mice, an effect which was completely prevented by supplementation with safflower or evening primrose oil but not hydrogenated coconut oil. In the liver phospholipids of the diabetic mice, dihomo-gamma-linolenic acid was proportionally increased, an effect reduced by supplementation with safflower oil but not evening primrose or hydrogenated coconut oils. In the liver triglycerides of the diabetic mice, gamma-linolenic acid, dihomo-gamma-linolenic acid and arachidonic acid were all proportionally decreased, effects which were also prevented by safflower or evening primrose oil but not hydrogenated coconut oil. Alopecia and dry scaly skin were prominent in the diabetic mice but less extensive in the diabetic mice supplemented with EFA.

Animals↗
PubMed1985

Magnesium deficiency in the rat increases tissue levels of docosahexaenoic acid.

The effects of magnesium deficiency on tissue levels of total lipids and fatty acids were evaluated. Sprague-Dawley rats were fed a magnesium-deficient diet for 14 wk with controls being pair-fed to the deficient rats. Compared to the controls, serum and 24-h urinary magnesium levels were markedly lower in the magnesium-deficient rats. Serum cholesterol and total phospholipids were significantly higher in the magnesium-deficient rats than in the controls. Edema and polycystic degeneration of the kidneys were present in the magnesium-deficient rats. Kidney total phospholipids and triacylglycerols were significantly lower in the magnesium-deficient rats than in the controls. The main change in tissue fatty acid composition in magnesium deficiency was the higher docosahexaenoic acid (22:6n-3) in serum, liver and aorta than in controls. The possible relationship of these findings to human alcoholism is discussed.

Animals↗