Sex differences in hepatic fatty acid uptake reflect a greater affinity of the transport system in females

1992 ◽  
Vol 263 (3) ◽  
pp. G380-G385 ◽  
Author(s):  
D. Sorrentino ◽  
S. L. Zhou ◽  
E. Kokkotou ◽  
P. D. Berk
Keyword(s):  
Plasma Membrane ◽  
Fatty Acid ◽  
Transport System ◽  
Fatty Acid Uptake ◽  
Surface Expression ◽  
Female Rats ◽  
Acid Uptake ◽  
Fatty Acid Binding ◽  
Male And Female Rats

In this study, we examined the hypothesis that the reported sex difference in hepatic free fatty acid (FFA) uptake involves the putative FFA transport system, the plasma membrane fatty acid binding protein (FABPpm). In hepatocytes isolated from both male and female rats, initial [3H]oleate uptake velocity reflected transmembrane influx and not subsequent metabolism and was a saturable function of the unbound oleate concentration. Although Vmax values were similar (61 +/- 2 vs. 65 +/- 5 pmol.min-1.5 x 10(4) cells-1 for females and males, respectively), the apparent Km was significantly smaller in females (40 +/- 4 vs. 90 +/- 11 nM; P less than 0.05), reflecting faster influx velocities in female cells over a range of unbound oleate concentrations. The oleate efflux rate constant was also greater in females (0.280 +/- 0.014 vs. 0.198 +/- 0.020 min-1; P less than 0.05) despite their greater hepatic content of cytosolic FABP. Finally, despite the greater rates of transmembrane FFA flux in female hepatocytes, the surface expression of FABPpm was virtually identical in the two sexes (2.5 +/- 0.5 vs. 2.4 +/- 0.4 microgram/10(6) cells). Collectively, these data indicate that at FFA-to-albumin ratios occurring in vivo the plasma membrane of female hepatocytes transports oleate bidirectionally at a greater rate than that of male hepatocytes. A sex-related difference in the functional affinity of FABPpm for FFA appears the most likely explanation for the greater oleate uptake in females.

Common mechanisms of monoacylglycerol and fatty acid uptake by human intestinal Caco-2 cells

2001 ◽  
Vol 281 (4) ◽  
pp. C1106-C1117 ◽  
Author(s):  
Shiu-Ying Ho ◽  
Judith Storch
Keyword(s):  
Plasma Membrane ◽  
Fatty Acid ◽  
Monomer Concentration ◽  
Protein S ◽  
Fatty Acid Uptake ◽  
Fatty Acid Transport ◽  
Acid Uptake ◽  
Fatty Acid Binding ◽  
Bound Lipids ◽  
Kinetics Of

Free fatty acids (FFA) and sn-2-monoacylglycerol ( sn-2-MG), the two hydrolysis products of dietary triacylglycerol, are absorbed from the lumen into polarized enterocytes that line the small intestine. Intensive studies regarding FFA transport across the brush-border membrane of the enterocyte are available; however, little is known about sn-2-MG transport. We therefore studied the kinetics of sn-2-MG transport, compared with those of long-chain FFA (LCFA), by human intestinal Caco-2 cells. To mimic postprandial luminal and plasma environments, we examined the uptake of taurocholate-mixed lipids and albumin-bound lipids at the apical (AP) and basolateral (BL) surfaces of Caco-2 cells, respectively. The results demonstrate that the uptake of sn-2-monoolein at both the AP and BL membranes appears to be a saturable function of the monomer concentration of sn-2-monoolein. Furthermore, trypsin preincubation inhibits sn-2-monoolein uptake at both AP and BL poles of cells. These results suggest that sn-2-monoolein uptake may be a protein-mediated process. Competition studies also support a protein-mediated mechanism and indicate that LCFA and LCMG may compete through the same membrane protein(s) at the AP surface of Caco-2 cells. The plasma membrane fatty acid-binding protein (FABPpm) is known to be expressed in Caco-2, and here we demonstrate that fatty acid transport protein (FATP) is also expressed. These putative plasma membrane LCFA transporters may be involved in the uptake of sn-2-monoolein into Caco-2 cells.

Caprenin 1. Digestion, Absorption, and Rearrangement in Thoracic Duct-Cannulated Rats

1991 ◽  
Vol 10 (3) ◽  
pp. 325-340 ◽  
Author(s):  
D. R. Webb ◽  
R. A. Sanders
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Female Rats ◽  
Acid Uptake ◽  
Long Chain Fatty Acids ◽  
Male And Female ◽  
Medium Chain ◽  
Male And Female Rats ◽  
Long Chain ◽  
Chain Fatty Acids

Caprenin (CAP) is a triglyceride that primarily contains caprylic (C8:0), capric (C10:0), and behenic (C22:0) acids. This study was undertaken to determine whether or not CAP is qualitatively digested, absorbed, and rearranged like other dietary fats and oils that contain these medium-chain and very long-chain fatty acids. In vitro results showed that neat CAP, coconut oil (CO) and peanut oil (PO) were hydrolyzed by porcine pancreatic lipase. All of the neat triglycerides also were digested in vivo by both male and female rats. This was shown by the recovery of significantly more extractable lymphatic fat than with fat-free control animals and by the recovery of orally administered triglyceride-derived fatty acids in lymph triglycerides. However, substantially more PO (74%) and CO (51%) were recovered in lymph relative to CAP (10%). These quantitative differences are consistent with the fatty acid composition of each triglyceride and primary routes of fatty acid uptake. The 24-h lymphatic recovery of CAP-derived C8:0, C10:0, and C22:0 averaged 3.9%, 17.8%, and 11.2%, respectively, for male and female rats. The C8:0 and C10:0 results approximated those obtained with CO (2.0% and 16.3%, respectively). In contrast, the 24-h absorbability of C22:0 in CAP was significantly less than that seen in PO (55.4%). Finally, there was no evidence of significant rearrangement of the positions of fatty acids on glycerol during digestion and absorption. Those fatty acids recovered in lymphatic fat tended to occupy the same glyceride positions that they did in the neat administered oils. However, the lymph fats recovered from all animals dosed with fat emulsions were enriched with endogenous lymph fatty acids. It is concluded that CAP is qualitatively digested, absorbed, and processed like any dietary fat or oil that contains medium-chain and very long-chain fatty acids.

Effect of surface and intracellular pH on hepatocellular fatty acid uptake

1996 ◽  
Vol 271 (6) ◽  
pp. G1067-G1073
Author(s):  
C. Elsing ◽  
A. Kassner ◽  
W. Stremmel
Keyword(s):  
Fatty Acids ◽  
Plasma Membrane ◽  
Fatty Acid ◽  
Intracellular Ph ◽  
Outer Surface ◽  
Fatty Acid Uptake ◽  
Proton Gradient ◽  
Fatty Acid Transport ◽  
Acid Uptake ◽  
Acid Transport

Fatty acids enter hepatocytes, at least in part, by a carrier-mediated uptake mechanism. The importance of driving forces for fatty acid uptake is still controversial. To evaluate possible driving mechanisms for fatty acid transport across plasma membranes, we examined the role of transmembrane proton gradients on fatty acid influx in primary cultured rat hepatocytes. After hepatocytes were loaded with SNARF-1 acetoxymethyl ester, changes in intracellular pH (pHi) under different experimental conditions were measured and recorded by confocal laser scanning microscopy. Fatty acid transport was increased by 45% during cellular alkalosis, achieved by adding 20 mM NH4Cl to the medium, and a concomitant paracellular acidification was observed. Fatty acid uptake was decreased by 30% during cellular acidosis after withdrawal of NH4Cl from the medium. Cellular acidosis activates the Na+/H+ antiporter to export excessive protons to the outer cell surface. Inhibition of Na+/H+ antiporter activity by amiloride diminishes pHi recovery and thereby accumulation of protons at the outer surface of the plasma membrane. Under these conditions, fatty acid uptake was further inhibited by 57% of control conditions. This suggests stimulation of fatty acid influx by an inwardly directed proton gradient. The accelerating effect of protons at the outer surface of the plasma membrane was confirmed by studies in which pH of the medium was varied at constant pHi. Significantly higher fatty acid influx rates were observed at low buffer pH. Recorded differences in fatty acid uptake appeared to be independent of changes in membrane potential, because BaCl2 did not influence initial uptake velocity during cellular alkalosis and paracellular acidosis. Moreover, addition of oleate-albumin mixtures to the NH4Cl incubation buffer did not change the observed intracellular alkalinization. In contrast, after cells were acid loaded, addition of oleate-albumin solutions to the recovery buffer increased pHi recovery rates from 0.21 +/- 0.02 to 0.36 +/- 0.05 pH units/min (P < 0.05), indicating that fatty acids further stimulate Na+/H+ antiporter activity during pHi recovery from an acid load. It is concluded that carrier-mediated uptake of fatty acids in hepatocytes follows an inwardly directed transmembrane proton gradient and is stimulated by the presence of H+ at the outer surface of the plasma membrane.

Fatty acid uptake in Escherichia coli: regulation by recruitment of fatty acyl-CoA synthetase to the plasma membrane

1993 ◽  
Vol 71 (1-2) ◽  
pp. 51-56 ◽  
Author(s):  
Dev Mangroo ◽  
Gerhard E. Gerber
Keyword(s):  
Escherichia Coli ◽  
Plasma Membrane ◽  
Fatty Acid ◽  
Fatty Acid Uptake ◽  
Fatty Acyl ◽  
Acid Uptake ◽  
Bacterial Membranes ◽  
Rate Limiting Step ◽  
Triton X ◽  
Rate Limiting

Fatty acid uptake in Escherichia coli has been shown to be inhibited by starvation and to be reversed by a short preincubation of the starved cells with D- or L-lactate, succinate, and acetate; these effects on oleate uptake were due to regulation of the rate-limiting step which involves fatty acyl-CoA synthetase. Investigation into the mechanism of regulation of fatty acyl-CoA synthetase showed that D-lactate did not affect the activity of the enzyme directly. Fatty acyl-CoA synthetase was found to be activated by about 20-fold by Triton X-100 and by another 4-fold by the addition of bacterial membranes. D-Lactate treatment was shown to result in coisolation of fatty acyl-CoA synthetase with the plasma membrane; these results are consistent with the interpretation that recruitment of the enzyme to the plasma membrane by D-lactate results in its activation and consequently in the increased level of fatty acid uptake.Key words: fatty acid, uptake, regulation, recruitment, fatty acyl-CoA synthetase, Escherichia coli, plasma membrane.

scholarly journals DHHC4 and DHHC5 Facilitate Fatty Acid Uptake by Palmitoylating and Targeting CD36 to the Plasma Membrane

Cell Reports ◽  
2019 ◽  
Vol 26 (1) ◽  
pp. 209-221.e5 ◽  
Author(s):  
Juan Wang ◽  
Jian-Wei Hao ◽  
Xu Wang ◽  
Huiling Guo ◽  
Hui-Hui Sun ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Fatty Acid ◽  
Fatty Acid Uptake ◽  
Acid Uptake

Enterocyte fatty acid uptake and intestinal fatty acid-binding protein

2004 ◽  
Vol 32 (1) ◽  
pp. 75-78 ◽  
Author(s):  
P. Tso ◽  
A. Nauli ◽  
C.-M. Lo
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Binding Protein ◽  
Brush Border Membrane ◽  
Fatty Acid Uptake ◽  
Current Understanding ◽  
Fatty Acid Binding Proteins ◽  
Acid Uptake ◽  
Micellar Solubilization ◽  
Fatty Acid Binding

This article reviews our current understanding of the uptake of fatty acids by the enterocytes of the intestine. The micellar solubilization of fatty acids by bile salts and the factors regulating that process are discussed. The mechanism of how micellar solubilization of fatty acids promotes the uptake of fatty acids by enterocytes and their relative importance is reviewed. Additionally, discussion of the various fatty acid transporters located at the brush border membrane of the enterocytes is included. Finally, a summary of our current understanding of the function of fatty-acid-binding proteins inside enterocytes is provided.

Sign in / Sign up

Export Citation Format

Share Document