Effect of starvation on enzymes related to lipid metabolism in guinea-pig lungs

The changes in activities of acetyl CoA carboxylase, microsomal fatty acid elongation enzyme, choline phosphotransferase, triglyceride lipase, phospholipase A1 and phospholipase A2 were followed in guinea-pig lungs at 24, 48 and 72 h after food deprivation. Triglyceride lipase was elevated and phospholipase A1 and phospholipase A2 were unaffected, while the other activities decreased. The significance of these findings in relation to food deprivation is discussed.     

Multiple phospholipase activation by OX1 orexin/hypocretin receptors

We investigated coupling of OX(1) receptors to phospholipase activation and diacylglycerol generation in Chinese hamster ovary (CHO) cells using both biochemical and fluorescence "real-time" methods. The results indicate that at lowest orexin-A concentrations (highest potency), diacylglycerol generated results from phospholipase D activity. At 10-100-fold higher orexin-A concentrations, phospholipase C is activated, likely hydrolyzing phosphatidylinositol (PI) or phosphatidylinositol monophosphate (PIP) but not phosphatidylinositol bisphosphate (PIP(2)). At further 7-fold higher orexin-A concentrations, PIP(2) is hydrolyzed, releasing both diacylglycerol and inositol-1,4,5-trisphosphate. Thus, OX(1) orexin receptors connect to multiple phospholipase activities, apparently composed of at least one phospholipase D and two different phospholipase C activities. At low agonist concentrations, diacylglycerol and phosphatidic acid are the preferred products, and interestingly, it seems that even the primarily activated phospholipase C mainly works to increase diacylglycerol and not inositol-1,4,5-trisphosphate.     

Spontaneous phospholipase A activity of rat pancreatic homogenates]

Rat pancreas presents a spontaneous phospholipase A activity which appears before trypsin activation at optimal pH 6.5. The responsible enzyme is independent of pancreatic prophospholipase A, as can be seen through experiments done in the presence of trypsin inhibitors. On the other hand, this enzyme is distinct from excretory phospholipase which is more active and whose optimal pH is 8.8. Thermostability and insensibility of spontaneously active phospholipase A to DFP differentiate it from lipase, carboxyl-esterhydrolase and lysophospholipase, respectively.     

Enzymatic activities in the liver, and muscle nucleic acids, in swine receiving an unbalanced diet with an excess of methionine for 100 days

Twelve growing Swine were fed an 18% protein diet (Maize and Soja bean) for one hundred days containing either 0,6% sulfur amino acids (basal diet) or 0,6% and 1% DL-methionine added to the control diet. Such an excess, reduced food intake and body weight gain mainly during the "finishing period" (60 to 100 kg). The RNA/DNA and protein/DNA ratios in the muscle did not show any difference. Hepatic activities of some enzymes involved in glycolysis, gluconeogenesis and amino acid metabolism, were unchanged, except that of methionine adenosyl transferase, the first step of transsulfuration, which was induced in proportion with the amount of the methionine ingested. Swine seemed to adapt to the excessive methionine intake, which did not show any toxicity in our experimental conditions.     

Lipase activity of anaerobic bacteria on glycerol-tributyrate determined by gas-liquid chromatography]

Anaerobic bacteria are classified among other criteria by the presence or absence of phospholipase and lipase. The liquid gas chromatographic method detects with great sensibility the lipasic activity of the anaerobic bacteria. A liidolytic action has been demonstrated in Cl. perfringens.     

Effect of pectin and cellulose on formation and regression of gallstones in hamsters

Male Syrian hamsters were fed a lithogenic diet containing 7% cellulose or 4.2% pectin. After 50 days, pectin was 76% and cellulose 64% less lithogenic than the control diet. Hamsters fed the control diet for 50 days were maintained on that diet for another 50 days or fed diets containing cellulose or pectin. There was a 52% increase in gallstone incidence in hamsters continued on the control diet and a 9% increase in those on cellulose. Pectin promoted regression of gallstones (by 52%).     

Protective effect of tannic acid in mice receiving dietary lead

Summary Mice fed a diet containing both tannic acid and lead acetate showed increased weight gain and greater fecundity when compared with those on a diet containing lead acetate alone. The most significant improvement was provided by adding 2% tannic acid (wt/wt) to ground food containing 3% lead acetate. The affinity of tannic acid for heavy metals is suggested as a reason for this protective effect.     

Effect of pectin and cellulose on formation and regression of gallstones in hamsters

Summary Male Syrian hamsters were fed a lithogenic diet containing 7% cellulose or 4.2% pectin. After 50 days, pectin was 76% and cellulose 64% less lithogenic than the control diet. Hamsters fed the control diet for 50 days were maintained on that diet for another 50 days or fed diets containing cellulose or pectin. These was a 52% increase in gallstone incidence in hamsters continued on the control diet and a 9% increase in those on cellulose. Pectin promoted regression of gallstones (by 52%).Acknowledgments. This work was supported, in part, by a grant (HL-03299) and a Research Career Award (HL-00734) from the National Institutes of Health, and by funds from Mary L. Smith and the Commonwealth of Pennsylvania.     

Myocardial function and energy metabolism in carnitine-deficient rats

Carnitine is essential for mitochondrial metabolism of long-chain fatty acids and thus for myocardial energy production. Accordingly, carnitine deficiency can be associated with cardiomyopathy. To better understand this disease, we determined myocardial function and energy metabolism in a rat model of carnitine deficiency. Carnitine deficiency was induced by a 3- or 6-week diet containing N-trimethyl-hydrazine-3-propionate, reducing cardiac and plasma carnitine by 70-85%. Myocardial function was investigated in isolated isovolumic heart preparations. Carnitine-deficient hearts showed left ventricular systolic dysfunction, reduced contractile reserve, and a blunted frequency-force relationship independently of the substrate used (glucose or palmitate). After glycogen depletion, palmitate could not sustain myocardial function. Histology and activities of carnitine palmitoyl transferase, citrate synthase, and cytochrome c oxidase were unaltered. Thus, as little as 3-6 weeks of systemic carnitine deficiency can lead to abnormalities in myocardial function. These abnormalities are masked by endogenous glycogen and are not accompanied by structural alterations of the myocardium or by altered activities of important mitochondrial enzymes.     

Differential diurnal variations of anandamide and 2-arachidonoyl-glycerol levels in rat brain

The endogenous ligands of cannabinoid receptors, also known as endocannabinoids, have been implicated in many physiological and pathological processes of the central nervous system. Here we show that the levels of the two major endocannabinoids, anandamide and 2-arachidonoyl-glycerol (2-AG), in four areas of the rat brain, change dramatically between the light and dark phases of the day. While anandamide levels in the nucleus accumbens, pre-frontal cortex, striatum and hippocampus were significantly higher in the dark phase, the opposite was observed with 2-AG, whose levels were significantly higher during the light phase in all four regions. We found that the activity of the fatty acid amide hydrolase, which catalyzes the metabolism of anandamide, was significantly lower during the dark phase, thus providing a possible explaination for the increase in anandamide levels. However, the activities of monoacylglycerol lipase and diacylglycerol lipase, two of the possible enzymes catalyzing the degradation and biosynthesis of 2-AG, respectively, changed significantly only in the striatum. These data suggest that the levels of the two major endocannabinoids might be under the control of endogenous factors known to undergo diurnal variations, and underscore the different roles, suggested by previous studies, of anandamide and 2-AG in neurophysiological processes.Received 9 December 2003; received after revision 15 January 2004; accepted 20 January 2004     

Latent iron deficiency alters gamma-aminobutyric acid and glutamate metabolism in rat brain

A diet containing 18-20 mg iron/kg to young weaned rats for 8 weeks altered the metabolism of gamma-aminobutyric acid and glutamate in the central nervous system without affecting blood hemoglobin. Subsequent rehabilitation with 390 mg iron/kg diet for 2 weeks normalized these changes.     

The diet and gut microflora influence the distribution of enteroendocrine cells in the rat intestine

Several functions of the gut are locally influenced by peptides and biogenic amines released from enteroendocrine cells. The aim of the present study was to assess whether the luminal stimulus of diet or microbial flora or diet-microbial interactions have an influence on the distribution of enteroendocrine cells along the crypt-surface axes of the small and large intestine. The effects of diet and indigenous flora were investigated by comparing the numbers of argyrophil and serotonin immunoreactive cells in the jejunum and colon of germ free and conventional rats fed either a purified diet containing fine ingredients or a commercial diet containing crude fibre of cereal origin. The effects of human flora were analysed in germ-free rats inoculated with human faecal organisms. 1. Feeding the commercial diet reduced the number of argyrophil endocrine cells in the jejunum and serotonin immunoreactive cells in the colon of gern-free animals but increased the serotonin immunoreactive cells in the colon of conventional animals. 2. The rat flora increased the serotonin immunoreactive cells in the colon of animals fed a commercial diet and decreased in those fed a purified diet. 3. Inculation of human flora increased the numbers of serotonin immunoreactive cells both in the jejunum and colon. The results provide evidence that the dietary changes and diet-microbial interactions can affect the regional number of enteroendocrine cells.     

Latent iron deficiency alters gamma-aminobutyric acid and glutamate metabolism in rat brain

Summary A diet containing 18–20 mg iron/kg to young weaned rats for 8 weeks altered the metabolism of gamma-aminobutyric acid and glutamate in the central nervous system without affecting blood hemoglobin. Subsequent rehabilitation with 390 mg iron/kg diet for 2 weeks normalized these changes.     

Penetration of phospholipases A2 and C into the squid (Loligo pealii) giant axon.

Following 1 h exposure, the level of phospholipase A2 penetration into the axoplasm of the squid giant axon was 107 to 350% of that in the external media; corresponding values for phospholipase C were 18 to 31%. Phospholipases can therefore be used to study phospholipid function in axons since they can penetrate through connective tissue and Schwann cell to reach the axolemma.     

Effect of dietary cholic acid and cholesterol on liver and kidney cystathionase and cysteine sulfinate decarboxylase activities and taurine concentrations in the rat

Summary Hepatic cystathionase and cysteine sulfinate decarboxylase activities are drastically affected by cholic acid added to the diet without cholesterol. When cholic acid and cholesterol are given together, only cysteine sulfinate decarboxylase activity is changed. Neither kidney enzyme activity nor taurine concentrations in the liver and kidney are noticeably modified, whatever the diet.This research was supported by INSERM (Contract 78.152.3) and by CEA.     

Cell surface heparan sulfate proteoglycans and lipoprotein metabolism

Cell surface heparan sulfate proteoglycans are involved in several aspects of the lipoprotein metabolism. Most of the biological activities of these proteoglycans are mediated via interactions of their heparan sulfate moieties with various protein ligands, including lipoproteins and lipases. The binding of lipoproteins to heparan sulfate is largely determined by their apoprotein composition, and apoproteins B and E display the highest affinity for heparan sulfate. Interactions of lipoproteins with heparan sulfate are important for the cellular uptake and turnover of lipoproteins, in part by enhancing the accessibility of lipoproteins to lipoprotein receptors and lipases. Apoprotein B may interact with receptors without involving heparan sulfate. Heparan sulfate has been further implicated in presentation and stabilization of lipoprotein lipase and hepatic lipase on cell surfaces and in the transport of lipoprotein lipase from extravascular cells to the luminal surface of the endothelia. In atherosclerosis, heparan sulfate is intimately involved in several events important to the pathophysiology of the disease. Heparan sulfate thus binds and regulates the activity of growth factors, cytokines, superoxide dismutase and antithrombin, which contribute to aberrant cell proliferation, migration and matrix production, scavenging of reactive oxygen radicals and thrombosis. In this review we discuss the various roles of heparan sulfate proteoglycans in vascular biology, with emphasis on interactions of heparan sulfate with lipoproteins and lipases and the molecular basis of such interactions.     

Certain biochemical effects of garlic oil on rats maintained on high fat-high cholesterol diet

The feeding of a high fat-high cholesterol (HF-HC) diet to normal rats for 1 month increased the lipid components cholesterol and triglyceride in serum, liver and kidneys and decreased the serum albumin very significantly. Administration of garlic oil (100 mg/kg b. wt/day) for 1 month together with the HF-HC diet to another group almost nullified the lipid-increasing and albumin-decreasing effects of that diet. The reduction in total lipids, cholesterol and triglycerides and the restoration to normal level of serum albumin were highly significant in the garlic oil group. Adipose tissue triglyceride lipase activity was significantly increased in both the above groups with a much greater rise in the oil group.     

Certain biochemical effects of garlic oil on rats maintained on high fat-high cholesterol diet

Summary The feeding of a high fat-high cholesterol (HF-HC) diet to normal rats for 1 month increased the lipid components cholesterol and triglyceride in serum, liver and kidneys and decreased the serum albumin very significantly. Administration of garlic oil (100 mg/kg b. wt/day) for 1 month together with the HF-HC diet to another group almost nullified the lipid-increasing and albumin-decreasing effects of that diet. The reduction in total lipids, cholesterol and triglycerides and the restoration to normal level of serum albumin were highly significant in the garlic oil group. Adipose tissue triglyceride lipase activity was significantly increased in both the above groups with a much greater rise in the oil group.     

Ovarian stimulation by exogenous gonadotrophins in fetal ethanol-exposed immature rats

Adult pregnant rats were given either an ad libitum liquid diet containing 5% ethanol, a pair fed liquid diet or an ad libitum diet of rat chow and water administered throughout pregnancy and during the nursing period. The female offspring received either pregnant mare's serum gonadotrophin (PMSG) or PMSG followed by human chorionic gonadotrophin (hCG) at 30 days of age. The ovaries of fetal ethanol-exposed animals responded greater to the exogenous gonadotrophins with enhanced ovarian weights, increased numbers of ova shed, greater numbers of corpora lutea and antral follicles, and higher serum progesterone levels than in animals exposed to the control diets during gestation.     

Ovarian stimulation by exogenous gonadotrophins in fetal ethanol-exposed immature rats

Summary Adult pregnant rats were given either an ad libitum liquid diet containing 5% ethanol, a pair fed liquid diet or an ad libitum diet of rat chow and water administered throughout pregnancy and during the nursing period. The female offspring received either pregnant mare's serum gonadotrophin (PMSG) or PMSG followed by human chorionic gonadotrophin (hCG) at 30 days of age. The ovaries of fetal ethanol-exposed animals responded greater to the exogeneous gonadotrophins with enhanced ovarian weights, increased numbers of ova shed, greater numbers of corpora lutea and antral follicles, and higher serum progesterone levels than in animals exposed to the control diets during gestation.