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O S Privett

Publications and source records attributed to O S Privett.

At least 37 records · Page 2Linked to original sources
PubMed1977

Studies of effects of trans fatty acids in the diet on lipid metabolism in essential fatty acid deficient rats.

Effects of diets containing mixtures of safflower oil, hydrogenated coconut oil with elaidate of linolelaidate on growth, fatty acid composition, serum lecithin: cholesterol acyl transferase (LCAT) and postheparin plasma lipoprotein lipase activities in essential fatty acid (EFA) deficient rats were determined. Addition of trans fatty acids to the diet lowered the growth response to linoleic acid. Both elaidate and linolelaidate accumulated in the serum and liver, imparied the conversion of oleic acid to eicosatrienoic acid and linoleic acid to arachidonic acid, and the incorporation of eicosatrienoic acid into cholesteryl esters. Trans fatty acids also influenced the fatty acid composition of testicular lipids, but much lower amounts of these acids accumlated in tests than in liver or serum. Serum lecithin:cholesterol acyl transferase activity was elevated by an EFA deficiency, was unaffected by dietary elaidate, but was significantly decreased by linolelaidate. These effects were nullified by the addition of safflower oil to the diet. Postheparin plasma extrahepatic and hepatic lipase activities were also affected by an EFA deficiency, and by the addition of elaidate or linolelaidate alone or in combination with safflower oil to the diets of EFA deficient rats. It is suggested that trans fatty acids exhibit particular effects on the metabolism of lipids in addition to aggravation of an EFA deficiency.

Animals↗
PubMed1977

Direct transesterification of lipids in mammalian tissue for fatty acid analysis via dehydration with 2,2'-dimethoxypropane.

A method is described for the transesterification of lipids of mammalian tissues for fatty acid analysis by gas-liquid chromatography (GLC) that eliminates the extraction step of conventional procedures. The method involves the direct reaction of anhydrous HCl-methanol with the lipids in approximately 10 mg of tissue or 0.1 ml of serum after removal of water by reacting it with 2,2'-dimethoxypropane (DMP). Acetone and methanol produced from water in the sample, as well as the excess DMP, are evaporated prior to transesterification in order to eliminate the formation of artifacts from the solvents. The method was demonstrated with rat serum and brain tissue.

Animals↗
PubMed1976

Effects of dietary saturated and trans fatty acids on cholesteryl ester synthesis and hydrolysis in the testes of rats.

Studies were made of the enzymic synthesis and hydrolysis of cholesteryl esters in rat testes. Weanling rats were fed for 14 weeks diets containing 5% by wt of hydrogenated coconut oil (HCO), a concentrate of ethyl elaidate and linolelaidate (TRANS), devoid of essential fatty acids (EFA), or safflower oil (SAFF). Cholesterol esterifying activity was localized in the soluble fraction, and cholesteryl ester hydrolase activity was distributed in both particulate and soluble fractions obtained from tissue homogenates. The optimum pH was 6.0 for esterification and 6.9-7.0 for hydrolysis. Neither esterifying nor hydrolytic activity was affected by freezing and thawing, but both reactions were inhibited by heat or sonication. The animals of both the HCO and TRANS groups had developed an EFA deficiency before they were sacrificed. The EFA deficiency produced upon feeding the HCO diet had no apparent effect on the synthesis and hydrolysis of cholesteryl esters in rat testes. The TRANS diet influenced the development of the testes as judged by their size, and cholesterol esterifying and cholesteryl ester hydrolyzing activities were suppressed in the testes of the animals of this group. A major difference in the effects of the HCO and TRANS diets on the lipids of the tests was the relatively minor amount of eicosatrienoic acid (20:3) and the elevated level of docosapentaenoic acid (22:5) in the cholesteryl esters of the testicular lipids of the TRANS group.

Animals↗
PubMed1976

Effects of dietary saturated and trans fatty acids on tissue lipid composition and serum LCAT activity in the rat.

Groups of rats were fed from weaning with diets containing 5% by wt of hydrogenated coconut oil (HCO), safflower oil, or a concentrate of ethyl elaidate and linolelaidate (TRANS) as the sole source of dietary fat. Fatty acid composition of the lipid classes from serum, liver, heart, and kidney was determined, and the serum lecithin: cholesterol acyl transferase (LCAT) activities were assayed for each animal. Serum LCAT activity was increased by both the HCO and TRANS diets in the early stages of the development of an essential fatty acid (EFA) deficiency but was suppressed in the animals of the TRANS group as they became older. The HCO and TRANS groups exhibited changes in tissue lipid fatty acid composition, as well as reduced growth, characteristic of an EFA deficiency. Coversion of oleic acid to eicosatrienoic acid was impaired in the animals fed the TRANS diet, greatly increasing the octadecenoic acid content of the tissue lipids at the expense of eicosatrienoic acid. The TRANS diet also suppressed incorporation of eicosatrienoic acid into cholesteryl esters of tissue and serum, indicating that, when fed as the sole source of unsaturated fat, trans fatty acids influenced the metabolism of unsaturated fatty acids and cholesterol.

Acyltransferases↗
PubMed1976

Toxic effects of hydroperoxide injections on rat lung. A light microscopical and ultrastructural study.

Intravenous administration of methyl linoleate hydroperoxide (MLH) uniformly resulted in extensive damage to septal wall components of the rat lung; the severity of these changes paralleled the administered dosage. The target cell of injury appeared to be the capillary endothelial cell. Destructive changes within the plasma membrane suggested that the major toxic effect of MLH was directed against membranous structures. Ultrastructural analysis showed that these effects were more severe in the vitamin E-deficient animals. Secondary changes were characterized by interstitial and alveolar edema, and degenerative changes within alveolar pneumocytes. Reparative proliferation of type 2 pneumocytes first became evident in animals that survived two days. These observations provide an insight into the susceptibility and sequential damage to pulmonary tissue by hydroperoxides and serve as a guide for investigations of the toxic effects of other oxidants on lung.

Animals↗
PubMed1975

Studies of lipid class and fatty acid profiles of rat mammary tumors induced by 7, 12-dimethylbenz(a)anthracene.

The lipid class and fatty acid composition profiles of mammary glands of female rats fed a nutritionally adequate diet are compared to those of tumors induced in the mammary glands by intravenous injection of dimethylbenz(a)anthracene of animals fed the same diet. Ca. 95% of the lipids of the mammary glands of the control group of animals consisted of triglycerides; glycolipids and phospholipids were present in only minor amounts. In contrast, the lipids of the mammary tumors contained much lower amounts of neutral lipids and higher concentrations of phospholipids. The glycolipid fraction was a minor component of both tissues but differed greatly in composition. The composition of the phospholipid and neutral lipid fractions, particulary the latter, of the mammary tumors also differed from that of the mammary glands of the control animals. The neutral lipids of the tumor tissues contained elevated levels of free fatty acids and cholesterol and much lower concentrations of triglyceride compared to the mammary gland lipids. Differences also were observed in the fatty acid composition of tumor and mammary gland lipid. The greatest differences occurred in the concentrations of polyunsaturated fatty acids which were generally much higher in the tumor lipids.

Animals↗
PubMed1975

Ifluence of dietary fatty acids on membrane properties and enzyme activities of liver mitochondria of normal and hypophysectomized rats.

Studies are reported on the effects of diets containing fatty supplements with (A) a high concentration of arachidonate (46% concentrate of ethyl arachidonate), (B) a high concentration of linoleate (corn oil), and (C) an essential fatty acid deficient, fully saturated fat (hydrogenated coconut oil) upon lipid composition, membrane permeability, and enzyme activities of liver mitochondria of normal and hypophysectomized rats. The fatty supplements produced differences in the fatty acid composition of the liver mitochondria; hypophysectomy, in addition, influenced the neutral and phospholipid composition. Permeability, indicated by swelling properties, correlated generally with the degree of unsaturation and essential fatty acid content of the lipid of the mitochondria of the normal animals. The fatty supplements also influenced the enzyme acitivites of the mitochondria of the normal animals. The mitochondria of the hypophysectomized animals were less responsive to the differences in the dietary fat in both their swelling properties and enzyme activities. Although the relationship was complex, it appeared that the hypophysis was involved in the functions of essential fatty acids in liver mitochondria.

Adenosine Triphosphatases↗
PubMed1975

Fatty acid synthesis from 2-14C-acetate in rat testis mitochondrial and cytosol fractions in vitro.

An in vitro system for acetate incorporation into fatty acids by the mitochondrial and the cytosol fractions of rat testis is described. The rate of incorporation of acetate into fatty acids was twice as fast with the mitochondrial as with the cytosol fraction; both systems were stimulated in the presence of adenosine triphosphate, reduced nicotinamide adenine dinucleotide phosphate, coenzyme A, and MgC1(2). The optimum pH was between 7.0-7.5 for the mitochondrial fraction and between 6.5-8.0 for the cytosol fraction. Radio gas chromatography showed that palmitic acid was the most highly labeled acid, followed by stearic acid, in the mitochondrial fraction in accord with the pathway of de novo fatty acid synthesis. Some of the labeled acetate was also incorporated into the 16:1 and 18:1 fatty acids of this fraction. Distribution of radioactivity among the mitochondrial lipid classes was highest in the phospholipids and monoglycerides, followed by diglycerides and cholesterol; little radioactivity was present in the triglyceride fraction. These observations are in accord with studies of the incorporation of labeled metabolites into testicular lipids following intratesticular injection and indicate the validity of the in vitro system for studies of specific reactions occurring in vivo.

Acetates↗