scholarly journals Metabolic fate of oleic acid derived from lysosomal degradation of cholesteryl oleate in human fibroblasts

1996 ◽  
Vol 37 (11) ◽  
pp. 2271-2279
Author(s):  
J E Groener ◽  
W Bax ◽  
B J Poorthuis
1996 ◽  
Vol 316 (3) ◽  
pp. 847-852 ◽  
Author(s):  
Jennifer S. BRUCE ◽  
Andrew M. SALTER

Unlike other saturated fatty acids, dietary stearic acid does not appear to raise plasma cholesterol. The reason for this remains to be established, although it appears that it must be related to inherent differences in the metabolism of the fatty acid. In the present study, we have looked at the metabolism of palmitic acid and stearic acid, in comparison with oleic acid, by cultured hamster hepatocytes. Stearic acid was taken up more slowly and was poorly incorporated into both cellular and secreted triacylglycerol. Despite this, stearic acid stimulated the synthesis and secretion of triacylglycerol to the same extent as the other fatty acids. Incorporation into cellular phospholipid was lower for oleic acid than for palmitic acid and stearic acid. Desaturation of stearic acid, to monounsaturated fatty acid, was found to be greater than that of palmitic acid. Oleic acid produced from stearic acid was incorporated into both triacylglycerol and phospholipid, representing 13% and 6% respectively of the total after a 4 h incubation. Significant proportions of all of the fatty acids were oxidized, primarily to form ketone bodies, but by 8 h more oleic acid had been oxidized compared with palmitic acid and stearic acid.


1998 ◽  
Vol 45 (2) ◽  
pp. 385-392
Author(s):  
V Chigorno ◽  
M Valsecchi ◽  
S Sonnino

Preparation of radioactive GM3 species containing isotopically labeled C18 sphingosine or C20 sphingosine is reported and their use for studying some aspects of the sphingolipid biosynthesis in cells is discussed. Human fibroblasts in culture that have only C18 sphingolipids and GM3 as the major gangliosides, were fed with the two radioactive GM3 species. The radioactive gangliosides were taken up by the cells and metabolized. The analyses of the radioactivity metabolic fate, in this model provides the following information. i--About 70-80% of the total catabolic sphingosine is re-cycled for biosynthesis of complex sphingolipids. ii--A small amount of the catabolic C20 sphingosine was re-cycled for biosynthesis of C20 sphingolipids, thus yielding complex lipids that are not naturally present in fibroblast cells. iii--A regulatory step in the biosynthesis of sphingolipid species differring long chain base content, C18 or C20 sphingosine, is in some way involved in the first steps of sphingolipid biosynthesis, and thus plays a decisive role in the availability of the long chain bases.


1988 ◽  
Vol 252 (2) ◽  
pp. 375-379 ◽  
Author(s):  
M Trinchera ◽  
U Wiesmann ◽  
M Pitto ◽  
D Acquotti ◽  
R Ghidoni

Cultured human fibroblasts were fed with two differently labelled sulphatide molecules [one labelled on C-3 of the sphingosine (Sph) moiety [(Sph-3H]sulphatide), the second on C-1 of stearic acid [(stearoyl-14C]sulphatide)], and the intracellular metabolic fate of radioactivity was monitored. Incorporated radioactivity was almost all recovered in the total lipid extract, regardless of the labelling position of the added sulphatide; however, large differences in the level of incorporation occurred among labelled glycosphingolipids. For example, sphingomyelin was present as the major radiolabelled lipid after [Sph-3H]-sulphatide incubation, but was detectable only in trace amounts after [stearoyl-14C]sulphatide administration; in the latter case the radioactivity was located predominantly in glycerophospholipids. From this finding it can be inferred that the free long-chain base (sphingosine) that originates from lysosomal catabolism of sulphatide is mainly, and quite specifically, utilized for sphingomyelin biosynthesis, whereas the ceramide moiety is not; conversely the fatty acid released from ceramide is non-specifically re-utilized for phospholipid biosynthesis.


1998 ◽  
Vol 336 (1) ◽  
pp. 201-205 ◽  
Author(s):  
Derek C. RADISKY ◽  
Jerry KAPLAN

Examination of the mechanism of intracellular iron recovery from lysosomally-degraded ferritin in vivo has been complicated by the continuous flux of cellular iron through ferritin molecules. Here we incubated human fibroblasts with cationic ferritin, a derivative of horse spleen ferritin, as a technique for delivering immunologically distinct ferritin molecules directly to lysosomes. Using this method, we found increased endogenous ferritin levels after the cellular degradation of cationic ferritin, demonstrating that cells can utilize lysosomal ferritin to produce increased cytosolic ferritin levels. Further, using an in vitro assay, we showed that isolated lysosomes degrade endogenous ferritin in a time- and temperature-dependent manner. These results are consistent with a model in which cytosolic ferritin is taken into the lysosomes and degraded. The solubilized iron from the ferric core could then be transported across the lysosomal membrane back into the cytosol.


Lipids ◽  
1993 ◽  
Vol 28 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Michael Miller ◽  
Mahnaz Motevalli ◽  
David Westphal ◽  
Peter O. Kwiterovich

1996 ◽  
Vol 49 (11) ◽  
pp. 1243 ◽  
Author(s):  
WM Best ◽  
BC Mortimer ◽  
TG Redgrave ◽  
RV Stick

A fluorescent analogue of cholesteryl oleate , namely 22-[ethyl(2'-naphthyl)amino]-23,24-dinorchol-5-en-3β-yl oleate, has been prepared from a steroidal carboxylic acid, 2-naphthylamine and oleic acid.


Author(s):  
Glennelle Washington ◽  
Philip P. McGrath ◽  
Peter R. Graze ◽  
Ivor Royston

Herpes-like viruses were isolated from rhesus monkey peripheral blood leucocytes when co-cultivated with WI-38 cells. The virus was originally designated rhesus leucocyte-associated herpesvirus (LAHV) and subsequently called Herpesvirus mulatta (HVM). The original isolations were from juvenile rhesus monkeys shown to be free of antibody to rhesus cytomegalic virus. The virus could only be propagated in human or simian fibroblasts. Use of specific antisera developed from HVM showed no relationship between this virus and other herpesviruses. An electron microscopic study was undertaken to determine the morphology of Herpesvirus mulatta (HVM) in infected human fibroblasts.


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