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S C Cunnane

Publications and source records attributed to S C Cunnane.

At least 127 records · Page 7Linked to original sources
PubMed1985

Contrasting effects of low or high copper intake on rat tissue lipid essential fatty acid composition.

The effects of low copper intake or copper supplementation on the metabolism of stearic acid have been studied previously, but their effects on essential fatty acids have not been reported. Male Sprague-Dawley rats were fed for 12 weeks on pelleted semi-synthetic diets containing less than 1 mg/kg copper (low copper), 6 mg/kg (copper control), or 250 mg/kg copper (copper supplemented). The fatty acid composition of the total phopholipids and triglycerides of plasma, liver, heart and adipose tissue was analyzed by gas liquid chromatography. In low copper rats compared to controls, palmitic and oleic acids were decreased but stearic acid and docosahexaenoic acid were increased in plasma, liver and heart phopholipids. Arachidonic acid was also increased in plasma and liver phospholipids in low copper rats. In liver triglycerides, linoleic and arachidonic acids were increased but palmitic and oleic acid were decreased in low copper rats. Copper supplementation had the opposite effect; palmitic and oleic acids were increased in phospholipids and triglycerides whereas essential fatty acids were generally decreased. Hence, copper not only has a direct effect on the desaturation of stearic acid but also has significant effects on the tissue lipid composition of essential fatty acids.

Adipose Tissue↗
PubMed1985

Effect of ethanol on liver triglycerides and fatty acid composition in the golden Syrian hamster.

In choice situations, the golden Syrian hamster shows a strong preference to drink an ethanol solution to water alone. Because of the known effects of ethanol on lipid metabolism, its effects on liver fatty acids were therefore studied in the hamster. After a period of 8 weeks during which hamsters had consumed water containing 10% ethanol (4 weeks) and then 15% ethanol (4 weeks), the liver was significantly increased in weight, an effect which was shown to be due to fat accumulation as triglyceride. The fatty acid composition of the liver triglycerides and phospholipids was altered such that monounsaturated fatty acids were very significantly increased and both n-6 and n-3 essential fatty acids were proportionally decreased.

Animals↗
PubMed1984

Essential fatty acids in plasma, red blood cells and liver phospholipids in common laboratory animals as compared to humans.

Essential fatty acids were estimated in plasma, red blood cells and liver total phospholipids in rats, mice, hamsters, guinea pigs, rabbits and humans. There were large species differences, suggesting that different species levels should be borne in mind when choosing an animal for a particular study. The 2 species most susceptible to atheroma, the guinea pig and the rabbit, had very high levels of linoleic acid and low levels of linoleic acid metabolites. n-3 fatty acid levels were low in guinea pigs and rabbits and the ratio of n-3 to n-6 fatty acids also was low in the rat. Mice and hamsters had the highest n-3 levels, suggesting they may be the best species to use for studies on the roles of n-3 essential fatty acids. Mice and hamsters and, in some respect rats, were closest to humans in their fatty acid patterns.

Animals↗
PubMed1984

Linoleic acid and arachidonic acid metabolism in human peripheral blood leucocytes: comparison with the rat.

Peripheral blood leucocytes from human male volunteers and from male rats were incubated in vitro in the presence of 14C-labelled linoleic acid [( 14C]LA) or 3H-labelled arachidonic acid [( 3H]AA). The time-course of [14C]LA and [3H]AA incorporation into human leucocyte total lipids was maximal at 80-90% of the initial dose within 20-30 min of dosing the cells. Compared with mixed leucocytes, isolated polymorphonuclear leucocytes were only marginally different in the differential incorporation of [14C]LA and [3H]AA into total lipids. In human leucocytes, [14C]LA was incorporated initially into triglycerides but predominantly into phosphatidylcholine thereafter. In the rat, [14C]LA remained as the free acid (63%), with lesser amounts entering the phospholipids (9%), monoglycerides-diglycerides (12%) and triglycerides (less than 1%). Utilization of [14C]LA by the delta 6-desaturase was only a minor route of its metabolism in both human and rat leucocytes. 3H-labelled prostaglandins E2 and F2 alpha accounted for up to 30% of the radioactivity released into the incubation medium from human leucocytes incubated with [3H]AA for 60 min. Stimulation of phagocytosis in the human leucocytes with latex beads or with unopsonized zymosan did not alter the differential incorporation of [14C]LA or [3H]AA into the leucocyte lipid fractions.

Adult↗
PubMed1984

Accumulation of linoleic and gamma-linolenic acids in tissue lipids of pyridoxine-deficient rats.

Young male Sprague-Dawley rats were fed diets containing added pyridoxine . HCl at 22 mg/kg (control), 0 mg/kg or 88 mg/kg for 6 weeks. In comparison with control or pyridoxine-supplemented (+PN) rats, growth of the pyridoxine-deficient (-PN) rats was significantly less after 2 weeks. After 6 weeks, liver weight was higher but thymus and epididymal fat weights, in relation to body weight, were significantly lower in -PN compared to control rats. In -PN rats, phospholipid levels of linoleic and gamma-linolenic acids were increased, but arachidonic acid was decreased compared to controls in plasma, liver, thymus and skin. In liver triglycerides from -PN rats, all essential fatty acids (n3 and n6) were increased compared to both control and +PN rats. The n3 essential fatty acids were significantly increased in plasma, liver, and thymus phospholipids in the +PN compared to control rats. These results support previous reports of an effect of pyridoxine on essential fatty acid metabolism and suggest that both linoleic desaturation and gamma-linolenic acid elongation may be impaired in -PN rats. In addition, the accumulation of essential fatty acids in the liver triglycerides of -PN rats suggests that essential fatty acid turnover between triglyceride and phospholipid may be influenced by pyridoxine.

Adipose Tissue↗
PubMed1984

Essential fatty acids in tissue phospholipids and triglycerides of the zinc-deficient rat.

This study addressed the possibility that zinc deficiency has different effects on the fatty acid composition of triglyceride compared to total phospholipid. Male weanling Sprague-Dawley rats were maintained for 6 weeks on a semisynthetic diet deficient in zinc (3 mg/kg zinc). Control rats (40 mg/kg zinc) were pair-fed. Lipid fractionation and fatty acid analysis were by thin-layer and gas chromatography, respectively. In zinc-deficient rats, the percentage of linoleic acid was increased or that of arachidonic acid was decreased in total phospholipids of plasma, liver, and testis, and in skin total lipids. Saturated and monounsaturated fatty acids were increased in the triglyceride of liver but decreased in the triglyceride of epididymal fat of zinc deficient rats. Essential fatty acids, as a proportion of total fatty acids, were decreased in triglyceride of liver but increased in triglyceride of epididymal fat of zinc-deficient rats. Our fatty acid data from tissue total phospholipids therefore support the concept that linoleic acid desaturation is impaired in zinc deficiency.

Adipose Tissue↗
PubMed1983

Uteroplacental dysfunction and prostaglandin metabolism in zinc deficient pregnant rats.

Relationships between perinatal mortality, disrupted utero-placental function and prostaglandin metabolism have been studied in Zn-deficient rats. Uterine contractility in vitro, placental blood flow in vivo, and uterine and placental prostaglandin synthesis from [1-14C] arachidonic acid in vitro were investigated at day 22 of pregnancy. High amplitude uterine contractions were almost completely eliminated and utero-placental blood flow was decreased by 85% by Zn deficiency. Synthesis of [1-14C]-prostaglandin E2, F2 alpha and 6-keto-F1 alpha from [1-14C] arachidonic acid decreased significantly in uterine tissue but increased in placentae. These possibly inter-related effects may contribute to the high perinatal mortality observed in Zn deficiency.

Animals↗
PubMed1982

Foetal mortality in moderately zinc-deficient rats is strictly related to the process of parturition: effect of maternal essential fatty acid supplementation.

1. Although disrupted parturition and high foetal losses have previously been reported in pregnant rats maintained on zinc-deficient diets this is the first report to differentiate between the effects of reduced Zn intake and the effects of reduced food intake on the outcome of pregnancy in the rat. 2. Rats maintained on a 0.5 mg Zn/kg diet for the last 7 d of gestation or on a 5 mg Zn/kg diet throughout gestation did not consume significantly less food than rats given 10 or 20 mg Zn/kg diets except during the last 2d of gestation. Pair-feeding of Zn-adequate rats (20 mg/kg) to those given low-Zn diets for the last 2 d of gestation did not affect the outcome of pregnancy in these rats. 3. In the rats maintained throughout gestation on 5 mg Zn/kg or on 0.5 mg Zn/kg in the last 7 d of gestation, parturition onset and duration were not significantly altered. Foetal survival was very significantly reduced but only from day 22 onwards; before the onset of parturition, foetal survival was not significantly affected by Zn deficiency during gestation. 4. Subcutaneous injection of evening primrose (Oenothera biennis) oil into rats throughout gestation enhanced foetal and neonatal survival in rats given 5 mg Zn/kg but reduced foetal survival in rats given 0.5 mg Zn/kg in the last 7 d of gestation. 5. The results suggest three points: (1) subtotal Zn deficiency during gestation in the rat jeopardises foetal survival at parturition without affecting the onset or duration of parturition, (2) foetal death in rats maintained on Zn-deficient diets occurs only in relation to parturition itself, (3) provided that Zn intake near term is at least 5 mg/kg, supplemental essential fatty acids (evening primrose oil) will reduce foetal mortality during parturition and in the neonatal period.

Animals↗
PubMed1982

Maternal essential fatty acid supplementation increases zinc absorption in neonatal rats: relevance to the defect in zinc absorption in acrodermatitis enteropathica.

Pregnant zinc deficient and zinc adequate rats were injected subcutaneously with evening primrose oil throughout gestation and for 3 days post partum. The nursing pups were injected intragastrically with zinc-65 on day 3 of live and sacrifices 4 h later. The % of the total injected zinc recovered in the carcass (minus the gut and gut contents) was significantly increased in those pups nursed by mothers injected with evening primrose oil, regardless of their dietary zinc intake. The fatty acid composition of the total lipid extract of the gut and gut contents of the neonates with increased zinc-65 absorption indicated that these pups had higher proportions of arachidonic acid and other metabolites of linoleic acid than did those with lower zinc-65 absorption. In other 3-day-old rat pups, intragastric injection of linoleic, gamma-linolenic or dihomo-gamma-linolenic acids along with the dose of zinc-65 very significantly increased zinc-65 absorption in a dose-related manner. Arachidonic acid however had no significant effect on zinc-65 absorption. Prostaglandin E1 caused a significant increase in zinc-65 absorption but prostaglandin E2 had no consistent effect. Indomethacin caused a dose-related inhibition of zinc-65 absorption.

Acrodermatitis↗
PubMed1981

Zinc deficiency increases the rate of delta 6 desaturation of linoleic acid in rat mammary tissue.

The effect of zinc deficiency on the delta 6-desaturation of [1-14C]linoleic acid was studied in mammary tissue microsomes from lactating rats. The rats were maintained on zinc-adequate (20 ppm zinc) or zinc-deficient (10 ppm zinc changing to 0.5 ppm zinc during last trimester) diets throughout gestation and for the first 3 days of lactation. Mammary tissue microsomes were incubated with [1-14C]linoleic acid and other samples of mammary tissue, mammary milk and the milk in the stomachs of the pups were analyzed for total fatty acid composition. In mammary microsomes from zinc-deficient rats, delta 6-desaturation of linoleic acid was 3.4 times greater than in microsomes from zinc-adequate rats. This change in metabolism of linoleic acid was reflected by comparable changes in the relative tissue and milk composition of linoleic and arachidonic acids and in the ratios of palmitic to palmitoleic acid, stearic to oleic acid and linoleic and arachidonic acid.

Animals↗
PubMed1980

The aquatic ape theory reconsidered.

Hardy's Aquatic Ape Theory (AAT) proposes that man progressed phylogenetically to the two-legged hairless creature that he is today via a semi-aquatic diversion which probably began during the Pliocene or perhaps as early as the Miocene era. It revolutionizes the human evolutionary story and in the process, challenges the classical anthropoid theory which has been the dominant theory of evolution since the time of Darwin. Possible reasons for the existance of many of man's previously unexplained characteristics (bipedalism, hairlessness, subcutaneous fat, bradycardia and others) is resolved without the proposal of any new or unreasonable hypotheses. Yet the AAT has been largely ignored. Morris and Morgan have supported the theory in the face of considerable criticism. This paper is a review of the theory and a collection of some of the opposing views presented by contemporary orthodox evolutionists.

Animals↗