Levels Of Oleate Research Articles

Short-term toxicity studies on some salts and oxides of tin in rats

Rats were fed on diets containing 0·0 (control), 0·03, 0·10, 0·30 or 1·00% of various salts or oxides of tin for periods of either 4 or 13 wk. The criteria examined included mortality, body-weight change, diet utilization, measurements of blood, urine and biochemical parameters, organ weights and gross and micropathology. No adverse effects were noted with any levels of stannous sulphide or oleate or of stannous or stannic oxides. Severe growth retardation, decreased food efficiency, slight anaemia and slight histological changes in the liver were observed with 0·3% or more of stannous chloride, orthophosphate, sulphate, oxalate and tartrate. The findings showed a marked difference in toxicity within the range of compounds studied. The signs of anaemia induced by certain cationic tin compounds included distinctly depressed haemoglobin concentrations, slight decreases in red cell counts and haematocrit value and a decreased level of serum iron. Dietary supplements of iron had a markedly protective effect against tin-induced anaemia, whereas a decrease of dietary iron aggravated the condition. These data suggest that some tin compounds may inhibit haematopoiesis, possibly by interfering with the intestinal absorption of iron. The no-effect level of the active tin salts examined was 0·1%, or 22–33 mg tin/kg/day, in a diet containing a liberal amount of iron. The level may be lower on diets marginal in iron.

Inheritance of Oleic and Linoleic Acids in Zea Mays L.1

The difference in the levels of oleate and linoleate in the triglycerides of the related R84 and Illinois High Oil (IHO) maize (Zea mays L.) strains is determined solely by the In locus. A single locus controls the 20% difference in oleate and linoleate between C103 and R84. At least two loci control the levels of oleate and linoleate in C103 and IHO. Strong maternal effects are exhibited in the reciprocal F1's of C103 and R84. In contrast, no maternal effects were detectable in IHO ✕ R84 and C103 ✕ IHO.

Effect of human growth hormone on fatty acid composition of serum lipids

The effects have been studied of human growth hormone (HGH) and of prolonged fasting on the fatty acid composition in serum of free fatty acids (FFA), triglycerides, cholesteryl esters and phospholipids. The serum fatty acid pattern was also studied in 3 acromegalic women.Following one injection of HGH, serum FFA concentrations rose and were highest at 8 h. This was mainly due to increased free oleic acid. Serum phospholipid concentrations fell and were lowest at 4 h.Prolongation of an overnight fast by 8 h also induced significant increases in serum FFA concentrations with an increase in free oleic acid, but of a smaller magnitude than after HGH injection; decreases occurred in free stearic and linoleic acids. The percentage level of phospholipid palmitate increased and that of linoleate decreased. In addition, the percentage level of triglyceride stearate decreased.When HGH was administered over 3 days, fasting serum FFA increased only on the 2nd day of treatment. The concentrations of serum phospholipid decreased steadily. An increase occurred in the percentage levels of triglyceride palmitate, cholesteryl oleate and phospholipid linoleate and eicosatrienoate. A decrease occurred in the percentage level of phospholipid oleate.Acromegalic patients had higher percentage levels of saturated acids in free and triglyceride fatty acids compared with normal controls. The high percentage of triglyceride saturated acids was the only characteristic that increased endogenous secretion and exogenously administered HGH had in common.

Regulation of the Metabolism of Rabbit Liver Mitochondria by Long Chain Fatty Acids and Other Uncouplers of Oxidative Phosphorylation

Abstract 1. Oleate, 2,4-dinitrophenol, and other uncouplers of oxidative phosphorylation have been compared with respect to their ability to stimulate the production of phosphoenolpyruvate from citric acid cycle intermediates and to alter the pathways of oxidation of pyruvate, glutamate, glutamine, and proline by rabbit liver mitochondria. 2. Oleate or 2,4-dinitrophenol stimulated the production of phosphoenolpyruvate from citrate or α-ketoglutarate even at concentrations of uncouplers which completely block respiratory chain-linked oxidative phosphorylation. 3. With malate or oxalacetate as substrate, uncouplers stimulated respiration and formation of phosphoenolpyruvate. In the presence of arsenite, production of phosphoenolpyruvate was blocked and pyruvate accumulated from these substrates. Added ATP restored phosphoenolpyruvate formation. 4. With pyruvate as substrate, low levels of uncouplers stimulated respiration, formation of citric acid cycle intermediates, and phosphoenolpyruvate. As the concentrations of uncouplers were increased, net formation of citrate, malate, and phosphoenolpyruvate was abolished, and pyruvate was diverted to acetoacetate. The level of added inorganic phosphate markedly influenced the rate of carboxylation of pyruvate. 5. With glutamate, glutamine, or proline as substrate, relatively low levels of oleate or 2,4-dinitrophenol gave optimal stimulation of respiration. However, at higher concentrations of uncouplers, formation of phosphoenolpyruvate was further increased without alteration of the respiratory rate. These effects may be explained by alterations in the relative rates of glutamic dehydrogenase and glutamicoxalacetic transaminase, the oxidation-reduction state of NAD(P), and the steady state level of oxalacetate. 6. The accumulated evidence supports the view that increased hepatic free fatty acids may facilitate gluconeogenesis in rabbit liver by uncoupling mitochondrial respiration.

Disproportionately higher levels of myocardial docosahexaenoate and elevated levels of plasma and liver arachidonate in hyperthyroid rats

The effects of hyperthyroidism on the metabolism and distribution of polyunsaturated fatty acids in rats were investigated. The animals were fed diets containing an equal amount (1% each) of linoleate and linolenate. Although the hepatic and plasma levels of the linolenate family of acids were not greatly affected by the hyperthyroidism, the heart of the hyperthyroid rat contained 425% more docosahexaenoate than did that of its euthyroid control. The hyperthyroidism was accompanied by accumulations of 85, 105, and 114% more arachidonic acid in the heart, plasma, and liver, respectively. Nevertheless, most of the total increases in plasma and liver fatty acids were due to the greater accumulations of palmitic, stearic, and oleic acids; the hepatic level of oleate was elevated by 204%. Hyperthyroid rats had 106% more total fatty acids in their hearts, this increase being due largely to the greater accumulation of polyunsaturated acids. The thyroid hormone appears to accelerate the biosynthesis of both arachidonate and docosahexaenoate, and these endogenous polyunsaturated acids are then selectively incorporated into the cardiovascular tissues. Other possible relationships between thyroid action and tissue polyenoic acids in "cold-stressed" animals are discussed.

Testicular lipids. II. Effect of unilateral cryptorchidism on fatty acids of testicular phospholipids and triglycerides.

Summary. Experiments were conducted using twenty-four mature male rabbits to determine the effects of short-term unilateral cryptorchidism on the fatty acid composition of testicular phospholipids and triglycerides. Total lipids were extracted from testes from unoperated control rabbits and from rabbits rendered unilaterally cryptorchid for 2, 4 or 6 days. Phospholipids and triglycerides were separated by thin layer chromatography. The methyl esters of the fatty acids in each fraction were separated and measured using gas-liquid chromatography. The phospholipid fraction was relatively high in the fatty acids palmitate, stearate and oleate whereas the triglyceride fraction contained relatively high levels of oleate, linoleate and palmitate. In the phospholipid fraction of the translocated testes, the proportion of palmitate rose after 2 days (P<0·01), returned to control levels at 4 days, then decreased (P<0·01) 6 days after translocation. Stearate, palmitaldehyde and stearaldehyde concentrations increased (P<0·001) in translocated testes at 4 and 6 days. Concentration of oleate in the phospholipid fraction decreased (P<0·01) after 2 or 4 days and linoleate was lower (P<0·05) than controls after 2 and 6 days of translocation. In the phospholipid fraction of scrotal testes, palmitate percentage increased (P<0·05) at 2 days, and linoleate and stearate decreased (P<0·05) at 2 and 6 days, respectively. Palmitate concentration in the triglyceride fraction of translocated testes increased (P<0·05) at 2 and 6 days as did stearate percentage (P<0·01) after 6 days. Myristate was also higher after 4 days of translocation (P<0·05). A decreased percentage of oleate was found in the triglyceride fraction of 4- and 6-day translocated testes. Triglycerides from the scrotal testes contained higher levels of palmitoleate (P<0·05) and myristate (P<0·05) than unoperated controls, but lesser percentages of stearate (P<0·01).

Control of Gluconeogenesis in Liver: I. GENERAL FEATURES OF GLUCONEOGENESIS IN THE PERFUSED LIVERS OF RATS

Abstract Gluconeogenesis from lactate, pyruvate, fructose, glycerol, amino acids, and other compounds was examined in the isolated rat liver perfused with buffer containing blood cells and serum albumin. The following observations were made. The condition of the liver remained good during 2 hours of perfusion at 37° as judged by its gross appearance, oxygen uptake, bile production, water content, and linear rates of glucose production from various substrates. The highest rate of glucose production (about 120 µmoles per g of liver per hour) was observed with saturating concentrations of fructose or dihydroxyacetone. This rate was double that with a saturating level of l-lactate or pyruvate, suggesting that the steps limiting gluconeogenesis from lactate or pyruvate lie before the formation of triose phosphate. The concentration of lactate for half-maximum gluconeogenesis was about 2 mm and that of pyruvate, about 1 mm. The same maximum rate of gluconeogenesis was observed with both substrates. Glycerol, d-glyceraldehyde, l-alanine, or l-serine at high concentrations supported rates of gluconeogenesis about double that found without added substrate (or approximately one-half the maximum rate with l-lactate). d-Lactate, other amino acids, and Krebs cycle intermediates were poor precursors when added singly. With a mixture of amino acids at plasma concentrations, basal glucose production was increased 3-fold and with 1 mm lactate it was doubled. The mean time for conversion of lactate to glucose was 75 sec. The rate of glucose utilization by the liver was low compared with gluconeogenesis. High levels of glucose did not suppress gluconeogenesis from saturating concentrations of lactate. Glucose was the major product of lactate, pyruvate, and fructose metabolism. Lactate production with fructose was greater than that with glucose. With pyruvate-2-14C, there was a 3-fold greater incorporation of isotope into glucose plus glycogen than into CO2. With pyruvate-1-14C, labeling of hexose was much less than that of CO2 and was 38% of that found with pyruvate-2-14C. A mathematical treatment of the isotopic data was developed. With certain assumptions, it was computed that pyruvate was converted to oxalacetate at twice the rate at which it was converted to acetyl coenzyme A, and that most of the acetyl-CoA formed from pyruvate entered the Krebs cycle. It was also deduced that the rate of conversion of oxalacetate to phosphopyruvate was 3-fold greater than the rate of conversion to citrate. There was no correlation between the rates of gluconeogenesis and ketogenesis. Lactate increased glucose production 4-fold but decreased ketogenesis by 70%. Physiological levels of oleate stimulated ketogenesis but not gluconeogenesis in livers from fasted or fed rats. In fed rats, octanoate increased ketogenesis 3-fold but did not affect gluconeogenesis.

A study of the effects of zinc and tin administered orally to mice over a prolonged period

Mice which received 1000 or 5000 ppm tin as sodium chlorostannate in drinking water or 5000 ppm tin as stannous oleate in their diet experienced a lower incidence of malignant lymphoma, hepatoma and pulmonary adenoma than untreated controls, and showed no other untoward effects. Mice which received 5000 ppm zinc as zinc oleate in the diet developed severe anaemia. Accordingly the level of zinc oleate was reduced to 1250 ppm. Prolonged feeding at this level failed to increase the incidence of malignant lymphoma or pulmonary adenomata above control levels. A slight but probably insignificant increase of hepatomata was recorded. The inclusion of 1000 or 5000 ppm zinc as zinc sulphate in the drinking water did not lead to an increased incidence of tumours at any site.

The fatty acid distribution in plasma, liver and aorta of cholesterol-fed and triton-treated rabbits

Summary In rabbits receiving either a control or a cholesterol-supplemented diet, the influence of sustained Triton treatment on the tissue lipid levels and fatty acid composition was examined. In the cholesterol-fed group, the total and esterified cholesterol levels of the plasma were significantly lowered by the Triton injections; the triglycerides and phospholipids were increased. In the livers on the other hand, both the amounts of cholesteryl ester and of triglyceride were lowered by the injection of the detergent. The deposition of lipid material in the aorta was inhibited notably. The cholesterol esterified fatty acid (CEFA) patterns of the plasma, liver and aorta were compared. When Triton was administered to cholesterol-fed animals the oleate/linoleate ratio in the plasma and liver CEFA were significantly lowered. Our observations suggest that the anti-atherogenic effect of Triton is not the result of its preventing the deposition of cholesteryl oleate in the intima, but rather of its lowering the absolute cholesteryl oleate level of the organism.