Biosynthesis of diacylglycerols by rat intestinal mucosa in vivo

1976 ◽  
Vol 54 (2) ◽  
pp. 137-144 ◽  
Author(s):  
W. C. Breckenridge ◽  
S. K. F. Yeung ◽  
A. Kuksis ◽  
J. J. Myher ◽  
M. Chan
Keyword(s):  
Fatty Acids ◽  
Intestinal Mucosa ◽  
Weight Fraction ◽  
Gas Liquid Chromatography ◽  
Long Chain Fatty Acids ◽  
Butter Oil ◽  
Arachidonic Acids ◽  
Layer Chromatography

The biosynthesis of diacylglycerols was studied in rat intestinal mucosa during in vivo absorption of a low molecular weight fraction of butter oil and of the corresponding medium and long chain fatty acids. The experimental fat solutions were given by stomach tube to the animals after a 24-h fast and mucosal scrapings were collected 3 h later. The lipids were isolated and the acylglycerols determined by combined thin-layer chromatography gas–liquid chromatography techniques and stereospecific analyses. Free fatty acid feeding led mainly to, sn-1,2-diacylglycerols, which contained exogenous and endogenous fatty acids. During triacylglycerol feeding, both.sn-1,2- and sn-2,3-diacylglycerols were recovered in significant amounts from the intestinal mucosa. The composition of the sn-2,3-diacylglycerols corresponded to that with exogenous fatty acids but the sn-1,2-diacylglycerols clearly contained both exogenous and endogenous fatty acids. In all cases it was possible to isolate endogenous sn-1,2-diacylglycerols made up largely of species with linoleic and arachidonic acids in the 2 position and palmitic and stearic acids in the 1 position, which apparently were not converted to triacylglycerols. The in vivo reacylation of 2-monoacylglycerols via both sn-1,2- and sn-2,3-diacylglycerols is in agreement with similar findings in vitro with everted sacs of rat intestinal mucosa.

Biosynthesis of triacylglycerols by rat intestinal mucosa in vivo

1976 ◽  
Vol 54 (2) ◽  
pp. 145-152 ◽  
Author(s):  
W. C. Breckenridge ◽  
S. K. F. Yeung ◽  
A. Kuksis
Keyword(s):  
Fatty Acids ◽  
Phosphatidic Acid ◽  
Free Fatty Acids ◽  
Intestinal Mucosa ◽  
Stereospecific Analysis ◽  
Weight Fraction ◽  
Exact Estimate ◽  
Gas Liquid Chromatography ◽  
Butter Oil

The structure of mucosal triacylglycerols was studied in rat intestinal mucosa in vivo during the absorption of a low molecular weight fraction of butter oil and of the corresponding free fatty acids of medium and long chain length. The mucosal lipids were isolated by solvent extraction and the acylglycerol structures were determined by combined AgNO3 – thin-layer chromatography and gas–liquid chromatography techniques and stereospecific analysis. Evidence was obtained for a rapid biosynthesis of triacylglycerols from diacylglycerols arising from the operation of both the monoacylglycerol and the phosphatidic acid biosynthetic pathways. Both sn-1,2- and sn-2,3-diacylglycerols appeared to be converted to triacylglycerols at significant rates, but a preferential utilization of sn-1,2-diacylglycerols could not be excluded. Endogenous dilution varied from a minimum of 5% during triacylglycerol biosynthesis from monoacylglycerols to 15% during their synthesis from free fatty acids, and was characterized by a preferential placement of the endogenous acids in the sn-3 and 2 positions of the triacylglycerol molecules. Exogenous myristic acid was preferentially associated with the sn-3 position, and stearic acid became preferentially bound to the sn-1 position. The complexity of the triacylglycerol end products prevented an exact estimate of the contribution of the phosphatidic acid pathway, but the acylglycerol structures were compatible with a minimum of 20% of total triacylglycerol yield at all times.

Diacylglycerol Biosynthesis in Everted Sacs of Rat Intestinal Mucosa

1975 ◽  
Vol 53 (11) ◽  
pp. 1170-1183 ◽  
Author(s):  
W. C. Breckenridge ◽  
A. Kuksis
Keyword(s):  
Fatty Acids ◽  
Phosphatidic Acid ◽  
Thin Layer ◽  
Free Fatty Acids ◽  
Thin Layer Chromatography ◽  
Intestinal Mucosa ◽  
Gas Liquid Chromatography ◽  
Acid Pathway ◽  
Layer Chromatography ◽  
Everted Sacs

The molecular specificity in the biosynthesis of diacylglycerols by rat intestinal mucosa was examined by means of radioactive markers, thin-layer chromatography with silver nitrate and gas-liquid chromatography with radioactivity monitoring. Bile salt micelles of alternately labeled monoacylglycerols and free fatty acids were incubated with everted sacs of intestinal mucosa for various periods of time and the diacylglycerols were isolated by solvent extraction and thin-layer chromatography. Stereospecific analyses of the X-1,2-diacylglycerols labeled from 2-monoacylgiycerols showed that the sn-1,2-isomers (45–55%) were slightly in excess of the sn-2,3-isomers (34–45%) with the X-1,3-diacylglycerols accounting for the rest of the radioactivity (5–10%). This suggests that racemic diacylglycerols may be intermediates in the resynthesis of dietary fat in rat intestinal mucosa. Detailed analyses of the molecular species of the sn-1,2-diacylglycerols labeled from free fatty acids revealed that 10–45% of the total did not contain the acid present in the 2-monoacylglycerol supplied, and therefore had originated from the phosphatidic acid pathway. These findings are at variance with those obtained in isolated microsomes, which have suggested an inhibition of the phosphatidic acid pathway by monoacylglycerols as well as have given evidence of an exclusive synthesis of sn-1,2-diacylglycerols from 2-monoacylglycerols.

In vitro and in vivo inhibition of renin by fatty acids.

1978 ◽  
Vol 234 (6) ◽  
pp. E593 ◽  
Author(s):  
T A Kotchen ◽  
W J Welch ◽  
R T Talwalkar
Keyword(s):  
Blood Pressure ◽  
Fatty Acids ◽  
Linoleic Acid ◽  
Angiotensin Ii ◽  
Neutral Lipids ◽  
Pressor Response ◽  
Arterial Blood ◽  
Arachidonic Acids

Circulating neutral lipids inhibit the in vitro renin reaction. To identify the inhibitor(s), free fatty acids were added to human renin and homologous substrate. Capric, lauric, palmitoleic, linoleic, and arachidonic acids each inhibited the rate of angiotensin I production in vitro (P less than 0.01). Inhibition by polysaturated fatty acids (linoleic and arachidonic) was less (P less than 0.01) after catalytic hydrogenation of the double bonds. To evaluate an in vivo effect of renin inhibition intra-arterial blood pressure responses to infusions of renin and angiotensin II (5.0 microgram) were measured in anephric rats (n = 6) before and after infusion of linoleic acid (10 mg iv). Mean increase of blood pressure to angiotensin II before (75 mmHg +/- 9) and after (90 +/- 12) linoleic acid did not differ (P greater than 0.05). However, the pressor response to renin after linoleic acid (18 +/- 3) was less (P less than 0.00)) than that before (102 +/- 13). In summary, several fatty acids inhibit the in vitro renin reaction, and in part inhibition is dependent on unsaturation. Linoleic acid also inhibits the in vivo pressor response to renin. These results suggest that fatty acids may modify the measurement of plasma renin activity and may also affect angiotensin production in vivo.

Release of essential fatty acids from the rat mesenteric vascular bed perfused in vitro: modulation by zinc

1990 ◽  
Vol 68 (7) ◽  
pp. 903-907 ◽  
Author(s):  
Stephen C. Cunnane ◽  
Bassam A. Nassar
Keyword(s):  
Fatty Acids ◽  
Essential Fatty Acids ◽  
Gas Liquid Chromatography ◽  
Long Chain Fatty Acids ◽  
Perfusion Medium ◽  
Vascular Bed ◽  
Mesenteric Vascular Bed ◽  
Long Chain ◽  
Chain Fatty Acids

The rat mesenteric vascular bed releases prostaglandins when perfused in vitro. The present study evaluated the effect of perfusion of the rat mesenteric vascular bed in vitro with a buffer containing 0, 3, 6, or 9 nM of added zinc on the release of essential fatty acids over a 150-min period. Long chain fatty acids in the mesenteric lipids and in total lipid of the perfusion effluent were assayed by gas liquid chromatography. The presence of 6 nM zinc in the perfusing buffer almost completely prevented the change in 16–22 carbon long chain fatty acids in the mesenteric phospholipids and decreased the release of free fatty acids in comparison to that occurring in the absence of additional zinc. The results sugest that physiological amounts of zinc in the perfusion medium reduce the release of essential fatty acids from rat mesenteric lipids.Key words: zinc, phospholipid, linoleic acid, arachidonic acid, prostaglandin.

scholarly journals Long chain fatty acids: in vitro cholecystokinin production and in vivo energy intake and body composition alteration

2011 ◽  
Vol 70 (OCE3) ◽  
Author(s):  
C. J. Harden ◽  
A. N. Jones ◽  
T. Maya-Jimenez ◽  
M. E. Barker ◽  
N. J. Hepburn ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Body Composition ◽  
Energy Intake ◽  
Long Chain Fatty Acids ◽  
Long Chain ◽  
Chain Fatty Acids

Glucose-stimulated acrolein production from unsaturated fatty acids

2004 ◽  
Vol 23 (2) ◽  
pp. 101-105 ◽  
Author(s):  
R Medina-Navarro ◽  
G Duran-Reyes ◽  
M Diaz-Flores ◽  
J J Hicks ◽  
J Kumate R
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Tissue Injury ◽  
Acid Product ◽  
Hydroperoxide Formation ◽  
Fatty Acid Product ◽  
Arachidonic Acids

Glucose auto-oxidation may be a significant source of reactive oxygen species (ROS), and also be important in the lipid peroxidation process, accompanied by the release of toxic reactive products. We wanted to demonstrate that acrolein can be formed directly and actively from free fatty acids in a hyperglycemic environment. A suspension of linoleic and arachidonic acids (2.5 mM) was exposed to different glucose concentrations (5, 10 and 15 mmol/L) in vitro. The samples were extracted with organic solvents, partitioned, followed at 255 / 267 nm, and analysed using capillary electrophoresis and mass spectroscopy. The total release of aldehydes significantly (P ≤ 0.01) increased from 1.0 to 5.1, 8.3 and 13.1 μmol/L after 6 hours of incubation, proportional to glucose concentrations. It was possible to verify a correlate hydroperoxide formation as well. Among the lipid peroxidation products, acrolein (5% of total) and its condensing product, 4-hydroxy-hexenal, were identified. From the results presented here, it was possible to demonstrate the production of acrolein, probably as a fatty acid product, due to free radicals generated from the glucose auto-oxidation process. The results led us to propose that acrolein, which is one of the most toxic aldehydes, is produced during hyperglycemic states, and may lead to tissue injury, as one of the initial problems to be linked to high levels of glucose in vivo.

Rumen hydrogenation of long-chain fatty acids from fish meal

1997 ◽  
Vol 1997 ◽  
pp. 129-129
Author(s):  
M.D. Carro ◽  
E.L. Miller ◽  
O.C. Fabb
Keyword(s):  
Fatty Acids ◽  
Fish Meal ◽  
Long Chain Fatty Acids ◽  
Flow Data ◽  
Significant Extent ◽  
Rumen Microorganisms ◽  
Long Chain

In one in vitro study Ashes et al. (1992) reported that C20 and C22 fatty acids (FA) from fish oil were not hydrogenated to any significant extent by rumen microorganisms. However, to our knowledge, no measurement on hydrogenation has been performed on fishmeal (FM) FA. The aim of this experiment was to study the in vivo and in situ rumen hydrogenation of long-chain FA of two different FM: FMl (60 g FA/g DM) and FM2 (85 g FA/g DM).Six sheep fitted with rumen cannulae and single duodenal cannulae were fed every 2 hours, receiving 1 kg/d of a 60:40 hay:concentrate diet, either alone (Control; C) or supplemented with 40 g FM/d (FMl and FM2). The experiment was carried out over four periods (two sheep received one of the diets in each period) and Cr-NDF was used as a marker to estimate duodenal flow. Data were subjected to analysis of variance using the ANOVA procedure of the Statistical Analysis Systems (SAS, 1994).

TISSUE CULTURE AND THE STUDY OF ANTICANCER AGENTS

1966 ◽  
Vol 44 (2) ◽  
pp. 339-343 ◽  
Author(s):  
Susan Tolnai
Keyword(s):  
Fatty Acids ◽  
Tumor Cells ◽  
Anticancer Agents ◽  
Antitumor Agents ◽  
Unsaturated Fatty Acids ◽  
Ascites Tumor ◽  
Mouse Tumors ◽  
Arachidonic Acids

In a quest for potential antitumor agents, more than 100 fatty acids and their derivatives were tested against transplantable mouse tumors with both in vivo and in vitro methods. Three compounds, 2,3-decenoic acid, linoleic acid, and linolenic acid, were found to arrest the growth of three types of ascites tumor cells, while 2-nonenoic, 10-undecenoic, oleic, and arachidonic acids were effective to a varying degree. The cytotoxic effects of these unsaturated fatty acids on monolayer cultures of Ehrlich ascites tumor cells and of normal mouse embryos were evaluated in experiments in which graded concentrations of the test materials incorporated in the culture medium were used.

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