Non-esterified fatty acids may regulate human leucocyte sodium pump activity

1986 ◽  
Vol 71 (6) ◽  
pp. 737-742 ◽  
Author(s):  
L. L. Ng ◽  
T. D. R. Hockaday
Keyword(s):  
Fatty Acids ◽  
Rate Constant ◽  
Acid Level ◽  
Sodium Pump ◽  
Efflux Rate ◽  
Fatty Acid Level ◽  
Esterified Fatty Acids ◽  
Pump Activity ◽  
Efflux Rate Constant

1. Human leucocyte sodium pump activity was studied in normal fasting subjects by measuring the ouabain-sensitive 22Na+ efflux rate constants. 2. This 22Na+ efflux rate constant was inversely related to the fasting plasma non-esterified fatty acid level (rs = −0.73, P < 0.0001). 3. An oral glucose load (40 g/m2 surface area) led to an increase in the leucocyte ouabain-sensitive 22Na+ efflux rate constant after 2 h (1.97 ± 0.25 to 2.44 ± 0.19 h−1, P < 0.0001, n = 11). There was a concomitant fall in the plasma non-esterified fatty acid level. 4. Incubation of leucocytes in vitro with 100 μmol/l linoleic acid inhibited the leucocyte ouabain-sensitive 22Na+ efflux rate constant (1.52 ± 0.27 vs 0.84 ± 0.24 h−1, P < 0.001, n = 8). 5. The leucocyte Na+,K+-dependent adenosine triphosphatase (Na+,K+-ATPase) activity was inhibited in vitro by long chain non-esterified fatty acids, especially when unsaturated. 6. Non-esterified fatty acids may account for some of the Na+,K+-ATPase inhibitory activity of plasma.

Leucocyte Electrolytes and Sodium Efflux Rate Constants in the Hypertension of Pre-Eclampsia

1980 ◽  
Vol 59 (s6) ◽  
pp. 199s-201s ◽  
Author(s):  
T. E. Forrester ◽  
G. A. O. Alleyne
Keyword(s):  
Blood Pressure ◽  
Rate Constant ◽  
Rate Constants ◽  
Sodium Pump ◽  
Efflux Rate ◽  
Sodium Efflux ◽  
Pump Activity

1. Leucocyte electrolytes were measured in pre-eclampsia and comparison was made with leucocytes from normal primigravidae and from the original pre-eclamptic subjects 6 months after delivery when blood pressure had returned to normal. 2. In pre-eclamptic subjects, leucocyte sodium was elevated and potassium depressed, and the rate constant for sodium efflux was depressed. 3. These changes returned to normal after delivery. 4. An increase in cellular sodium as a result of altered sodium pump activity may be the cause of hypertension in pre-eclampsia.

Effect of the Calcium Antagonist Verapamil on Human Leucocyte Sodium Transport in vitro

1985 ◽  
Vol 68 (2) ◽  
pp. 239-241 ◽  
Author(s):  
H. H. Gray ◽  
L. Poston ◽  
V. E. Johnson ◽  
P. J. Hilton
Keyword(s):  
Essential Hypertension ◽  
Calcium Antagonist ◽  
Sodium Transport ◽  
Rate Constants ◽  
Sodium Pump ◽  
Efflux Rate ◽  
Sodium Efflux ◽  
Pump Activity ◽  
External Calcium

1. Sodium efflux rate constants and intracellular sodium were measured in leucocytes from healthy volunteers in the presence and absence of the calcium antagonist verapamil hydrochloride. 2. Verapamil stimulated sodium pump activity and this effect was dependent on the presence of external calcium. 3. Verapamil has been reported to reverse the abnormality of sodium transport seen in leucocytes from patients with essential hypertension and the present study demonstrates that sodium pump activity in leucocytes from control subjects is also stimulated by exposure to verapamil in vitro. This direct cellular effect appears to be due to the calcium antagonist properties of the drug.

scholarly journals Identification of Tyr residues that enhance folate substrate binding and constrain oscillation of the proton-coupled folate transporter (PCFT-SLC46A1)

2015 ◽  
Vol 308 (8) ◽  
pp. C631-C641 ◽  
Author(s):  
Michele Visentin ◽  
Ersin Selcuk Unal ◽  
Mitra Najmi ◽  
Andras Fiser ◽  
Rongbao Zhao ◽  
...  
Keyword(s):  
Choroid Plexus ◽  
Rate Constant ◽  
Binding Pocket ◽  
Wild Type ◽  
Efflux Rate ◽  
High Affinity ◽  
Extracellular Compartment ◽  
Efflux Rate Constant ◽  
Opposite Compartment

The proton-coupled folate transporter (PCFT) mediates intestinal folate absorption and transport of folates across the choroid plexus. This study focuses on the role of Tyr residues in PCFT function. The substituted Cys-accessibility method identified four Tyr residues (Y291, Y362, Y315, and Y414) that are accessible to the extracellular compartment; three of these (Y291, Y362, and Y315) are located within or near the folate binding pocket. When the Tyr residues were replaced with Cys or Ala, these mutants showed similar (up to 6-fold) increases in influx Vmax and Kt/ Ki for [3H]methotrexate and [3H]pemetrexed. When the Tyr residues were replaced with Phe, these changes were moderated or absent. When Y315A PCFT was used as representative of the mutants and [3H]pemetrexed as the transport substrate, this substitution did not increase the efflux rate constant. Furthermore, neither influx nor efflux mediated by Y315A PCFT was transstimulated by the presence of substrate in the opposite compartment; however, substantial bidirectional transstimulation of transport was mediated by wild-type PCFT. This resulted in a threefold greater efflux rate constant for cells that express wild-type PCFT than for cells that express Y315 PCFT under exchange conditions. These data suggest that these Tyr residues, possibly through their rigid side chains, secure the carrier in a high-affinity state for its folate substrates. However, this may be achieved at the expense of constraining the carrier's mobility, thereby decreasing the rate at which the protein oscillates between its conformational states. The Vmax generated by these Tyr mutants may be so rapid that further augmentation during transstimulation may not be possible.

Inhibition of binding of gonadal steroids to serum binding proteins by non-esterified fatty acids: the influence of chain length and degree of unsaturation

1989 ◽  
Vol 120 (2) ◽  
pp. 175-179 ◽  
Author(s):  
C. Street ◽  
R. J. S. Howell ◽  
L. Perry ◽  
S. Al-Othman ◽  
T. Chard
Keyword(s):  
Fatty Acids ◽  
Protein Binding ◽  
Unsaturated Fatty Acids ◽  
Late Pregnancy ◽  
Sex Hormone Binding Globulin ◽  
Partial Purification ◽  
Normal Female ◽  
Esterified Fatty Acids ◽  
Vitro Binding

Abstract. The effect of non-esterified fatty acids (NEFA) on the in vitro binding of testosterone, 5-alpha dihydrotestosterone and estradiol E2 to sex hormone binding globulin (SHBG) was examined using pooled normal female serum, and SHBG and albumin fractions obtained from the partial purification of late pregnancy serum. A range of saturated and unsaturated fatty acids were examined for their effect on steroid-protein binding. In normal female serum, NEFA added at physiological concentrations disrupted steroid-protein binding. The shorter chain (C8–C12) saturated acids and the poly-unsaturated acids proved to be more effective inhibitors than the longer chain saturated or mono-unsaturated acids. The greatest inhibition was obtained with E2 whereas the binding of dihydrotestosterone was least affected. With partially purified SHBG, the same concentrations of NEFA were less effective at inhibiting the binding of dihydrotestosterone and testosterone but elicited the same effect with E2. The binding of steroids to albumin appeared to be unaffected by these concentrations of NEFA.

Free fatty acid level in rat liver after ingestion of polyunsaturated fatty acids

Lipids ◽  
1969 ◽  
Vol 4 (1) ◽  
pp. 77-79 ◽  
Author(s):  
Akira Yamamoto ◽  
Masahiro Isozaki ◽  
Takeshi Ishibe ◽  
Mitsuo Nishikawa
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Rat Liver ◽  
Acid Level ◽  
Free Fatty Acid Level ◽  
Fatty Acid Level

Erythrocyte 22Na Efflux and Urinary Sodium Excretion in Essential Hypertension

1980 ◽  
Vol 59 (s6) ◽  
pp. 195s-197s ◽  
Author(s):  
W. R. Fitzgibbon ◽  
T. O. Morgan ◽  
J. B. Myers
Keyword(s):  
Rate Constant ◽  
Sodium Excretion ◽  
Urinary Sodium Excretion ◽  
Urinary Sodium ◽  
Aetiological Factor ◽  
Efflux Rate ◽  
Artificial Medium ◽  
Sodium Efflux ◽  
Hypertensive Patients ◽  
Efflux Rate Constant

1. The rate constant for total 22Na efflux from erythrocytes was examined in patients with mild to moderate hypertension and in normotensive controls. No difference in 22Na efflux rate constant was found when the cells from both groups were incubated in artificial medium. When the cells from both groups were incubated in their own plasma, the rate constant for Na efflux was significantly elevated for hypertensive patients compared with controls (0.40 ± 0.02, 0.36 ± 0.01 respectively; P&lt;0.05). 2. In hypertensive patients sodium efflux rate constant varied inversely with 24 h urinary sodium excretion when erythrocytes were incubated in artificial medium (r = − 0.34, P&lt;0.05) or in plasma (r = −0.42, P&lt;0.05). No association between sodium efflux rate constant and urinary sodium excretion occurred in normotensive subjects. 3. These findings provide further evidence that sodium is an important aetiological factor in hypertension. In ‘salt-sensitive’ individuals dietary sodium may interact with the regulation of cellular sodium transport via both humoral and cellular mechanisms to elevate blood pressure.

scholarly journals Cocultured porcine granulosa cells respond to excess non-esterified fatty acids during in vitro maturation

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Meihong Shi ◽  
Marc-André Sirard
Keyword(s):  
Fatty Acids ◽  
Granulosa Cells ◽  
Epithelial Mesenchymal Transition ◽  
Differentially Expressed ◽  
Algorithm Analysis ◽  
Inflammatory Factors ◽  
Luteal Cell ◽  
Mesenchymal Transition ◽  
Esterified Fatty Acids

Abstract Background Non-esterified fatty acids (NEFAs) are one of the main lipid components of follicular fluid at concentrations that depend on circulating levels. Elevated levels of NEFAs impair oocyte quality, development potential, and may subsequently influence the metabolism and reproductive fitness of offspring. Granulosa cells (GCs) are the follicular cells that are closely communicating with the oocyte. However, the responses of GCs exposed to high levels of NEFAs when cocultured with cumulus-oocyte complexes (COCs), and how they attenuate the negative effects of NEFAs on oocytes, are unclear. Results To better understand this protective effect, monolayers of porcine GCs were cocultured with COCs during in vitro maturation (IVM) in the presence of elevated levels of NEFAs. Genomic expression analysis was conducted to explore the responses of the GCs to the elevated levels of NEFAs. After limma algorithm analysis, 1,013 genes were differentially expressed between GCs cultured with and without elevated NEFAs. Among them, 438 genes were upregulated and 575 were downregulated. The differentially expressed genes were enriched in pathways related to metabolism, inflammation, and epithelial-mesenchymal transition. Conclusions The pathways and upstream regulators suggested that the cocultured GCs responded to the elevated NEFAs with (1) inhibition of the transition from granulosa to luteal cell, (2) interactions of metabolism change, anti-inflammation, mitochondrial function, and cell transition, (3) intercommunication with cocultured COCs of anti-inflammatory factors.

THE EFFECT OF VARIOUS SACCHARIDES ON THE RELEASE OF NON ESTERIFIED FATTY ACIDS FROM ADIPOSE TISSUE IN VITRO

1962 ◽  
Vol 40 (4) ◽  
pp. 455-458 ◽  
Author(s):  
W. F. Perry ◽  
R. J. Tjaden
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Incubation Medium ◽  
Epididymal Adipose Tissue ◽  
Tissue Cell ◽  
Glycerol Phosphate ◽  
Esterified Fatty Acids ◽  
Adipose Tissue Cell ◽  
Other Substances

Rat epididymal adipose tissue was incubated in a phosphate–albumin medium to ascertain the effect of various saccharides and other substances on the release of non-esterified fatty acids (NEFA) into the medium. It was found that incubation with glucose, mannose, fructose, and 2-deoxy glucose resulted in less release of NEFA from the tissue into the incubation medium. Incubation with galactose, sucrose, lactose, D-ribose, D-xylose, L-xylose, D-arabinose, L-arabinose, D-lyxose, sodium pyruvate, glycerol, and glycerol phosphate showed no differences from the control in release of NEFA into the incubation medium. These results are consistent with the theory that the NEFA-lowering action of glucose is due to esterification of free fatty acid within the adipose tissue cell by glycerol phosphate.

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