scholarly journals Reconstitution of the lactate carrier from rat skeletal-muscle sarcolemma

1994 ◽  
Vol 299 (2) ◽  
pp. 533-537 ◽  
Author(s):  
F Wibrand ◽  
C Juel
Keyword(s):  
Skeletal Muscle ◽  
Time Course ◽  
Rat Skeletal Muscle ◽  
Lactate Transport ◽  
Exchange Inhibitor ◽  
Transport Inhibitors ◽  
Lactate And Pyruvate ◽  
Lactate Uptake ◽  
Fold Excess ◽  
Sarcolemmal Vesicles

The lactate carrier was solubilized from purified rat skeletal-muscle sarcolemma with the detergent decanoyl-N-methyl-glucamide and the solubilized carrier was reconstituted into phospholipid vesicles. Reconstituted proteoliposomes showed a faster time course of L-lactate uptake than did protein-free liposomes. The rate of L-lactate uptake into the proteoliposomes was inhibited by the lactate-transport inhibitors p-chloromercuribenzenesulphonate, diethyl pyrocarbonate, alpha-cyano-4-hydroxycinnamate and quercetin. In contrast, the anion-exchange inhibitor DIDS (4,4′-di-isothiocyanostilbene-2,2′-disulphonate) had almost no effect on the uptake. The extent of L-lactate uptake at equilibrium was not affected by the presence of the transport inhibitors, but was sensitive to osmotic strength. L-Lactate and pyruvate, but not D-lactate, inhibited L-lactate uptake when present at 10-fold excess. The properties of L-lactate transport in reconstituted proteoliposomes were similar to those observed in native sarcolemmal vesicles, i.e. the lactate carrier seems to retain its transport characteristics during the solubilization and reconstitution steps.

scholarly journals Effect of 2-chloropropionate on initial lactate uptake by rat skeletal muscle sarcolemmal vesicles

1996 ◽  
Vol 81 (5) ◽  
pp. 1973-1977 ◽  
Author(s):  
P. Granier ◽  
H. Dubouchaud ◽  
N. Eydoux ◽  
J. Mercier ◽  
C. Préfaut
Keyword(s):  
Skeletal Muscle ◽  
Initial Rate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Membrane Vesicles ◽  
Rat Skeletal Muscle ◽  
Lactate Transport ◽  
Sarcolemmal Membrane ◽  
Lactate Uptake ◽  
Sarcolemmal Vesicles

Granier, P., H. Dubouchaud, N. Eydoux, J. Mercier, and C. Préfaut. Effect of 2-chloropropionate on initial lactate uptake by rat skeletal muscle sarcolemmal vesicles. J. Appl. Physiol. 81(5): 1973–1977, 1996.—2-Chloropropionate (2-CP) is a halogenated monocarboxylic acid generally used to decrease blood lactate concentration in various metabolic states. To investigate whether it has an inhibitory effect on sarcolemmal lactate transport, we compared the initial rate of lactate transport in sarcolemmal membrane vesicles purified from 20 male Wistar rats with and without 2-CP. Transport by these vesicles was measured as uptake ofl-(+)-[U-14C]lactate under pH gradient-stimulated cisinhibition. The time courses of 1 mMl-(+)-lactate uptake into vesicles both with and without 10 mM 2-CP (l- ord-) displayed saturation kinetics. Lactate uptake values were lower with 10 mMl-2-CP and 10 mMd-2-CP in comparison to the control values. Both 10 mMl-2-CP and 10 mMd-2-CP significantly inhibited 1 mM l-(+)-lactate uptake (55.8 ± 9.1 and 53.5 ± 12.1%, respectively; P < 0.001), whereas a smaller inhibition was observed with a higher lactate concentration of 50 mM (40.2 ± 11.2 and 38.7 ± 12.4%; P < 0.001 and P < 0.05, respectively). However, a higher d-2-CP concentration (50 mM) increased the inhibition of pH-stimulated 1 mMl-(+)-lactate uptake (77.0 ± 9.4%; P < 0.001).d-2-CP had a trans-stimulation effect on the initial rate of lactate efflux of 1 mMl-(+)-lactate compared with baseline efflux (9.5 ± 0.8 vs. 5.1 ± 0.4 nmol ⋅ min−1 ⋅ mg protein−1; P < 0.05). 2-CP significantly inhibited the initial rate of lactate uptake in skeletal muscle sarcolemmal membrane vesicles. This result suggests that 2-CP is a nonstereoselective substrate of the lactate muscle carrier that impairs lactate transport.

scholarly journals Lactate transport activity in rat skeletal muscle sarcolemmal vesicles after acute exhaustive exercise

1999 ◽  
Vol 87 (3) ◽  
pp. 955-961 ◽  
Author(s):  
H. Dubouchaud ◽  
N. Eydoux ◽  
P. Granier ◽  
C. Préfaut ◽  
J. Mercier
Keyword(s):  
Skeletal Muscle ◽  
Time Course ◽  
Lactate Concentration ◽  
Treadmill Running ◽  
Exhaustive Exercise ◽  
Transport Activity ◽  
Rat Skeletal Muscle ◽  
Lactate Transport ◽  
Single Bout ◽  
Lactate Uptake

The effect of a single bout of exhaustive exercise on muscle lactate transport capacity was studied in rat skeletal muscle sarcolemmal (SL) vesicles. Rats were assigned to a control (C) group ( n = 14) or an acutely exercised (E) group ( n = 20). Exercise consisted of treadmill running (25 m/min, 10% grade) to exhaustion. SL vesicles purified from C and E rats were sealed because of sensitivity to osmotic forces. The time course of 1 mM lactate uptake in zero- trans conditions showed that the equilibrium level in the E group was significantly lower than in the C group ( P < 0.05). The initial rate of 1 mM lactate uptake decreased significantly from 2.44 ± 0.22 to 1.03 ± 0.08 nmol ⋅ min−1 ⋅ mg protein−1( P < 0.05) after exercise, whereas that of 50 mM lactate uptake did not differ significantly between the two groups. For 100 mM external lactate concentration ([lactate]), exhaustive exercise increased initial rates of lactate uptake (219.6 ± 36.3 to 465.4 ± 80.2 nmol ⋅ min−1 ⋅ mg protein−1, P < 0.05). Although saturation kinetics were observed in the C group with a maximal transport velocity of 233 nmol ⋅ min−1 ⋅ mg protein−1 and a Michealis-Menten constant of 24.5 mM, saturation properties were not seen after exhaustive exercise in the E group, because initial rates of lactate uptake increased linearly with external [lactate]. We conclude that a single bout of exhaustive exercise significantly modified SL lactate transport activity, resulting in a decrease in 1 mM lactate uptake and was associated with alterations in the saturable properties at [lactate] above 50 mM. These results suggest that changes in sarcolemmal lactate transport activity may alter lactate and proton exchanges after exhaustive exercise.

L(+)-Lactate Binding to a Protein in Rat Skeletal Muscle Plasma Membranes

1995 ◽  
Vol 20 (1) ◽  
pp. 112-124 ◽  
Author(s):  
Karl J. A. McCullagh ◽  
Arend Bonen
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membranes ◽  
Mass Range ◽  
Dependent Manner ◽  
Rat Skeletal Muscle ◽  
Lactate Transport ◽  
Sds Page ◽  
Lactate And Pyruvate ◽  
Potential Inhibitors ◽  
Dose Dependent

Biochemical studies were conducted to determine the location of a putative lactate transport protein in rat skeletal muscle plasma membranes (PM). PM (50-100 μg protein) were incubated with [U-14C] L(+)-lactate, in the presence or absence of unlabeled monocarboxylates or potential inhibitors, after which proteins were separated by SDS-PAGE. Gel slices (2 mm) were cut and analyzed for14C. [U-14C] L(+)-lactate was bound to plasma membranes in the 30 to 40 kDa molecular mass range. Binding of [U-14C] L(+)-lactate was inhibited by N-ethylmaleimide, unlabeled L-lactate and pyruvate, and in a dose dependent manner by α-cyano-4-hydroxycinnamate (r = 0.995), but not by cytochalasin-B. The inhibition of [U-14C] L(+)-lactate binding was similar to the inhibition of lactate transport. Therefore the transport of L(+)-lactate across skeletal muscle plasma membranes involves a polypeptide of 30 to 40 kDa. Key words: transport, affinity labeling

T3 increases lactate transport and the expression of MCT4, but not MCT1, in rat skeletal muscle

2003 ◽  
Vol 285 (3) ◽  
pp. E622-E628 ◽  
Author(s):  
Yuxiang Wang ◽  
Mio Tonouchi ◽  
Dragana Miskovic ◽  
Hideo Hatta ◽  
Arend Bonen
Keyword(s):  
Skeletal Muscle ◽  
Protein Expression ◽  
Gastrocnemius Muscle ◽  
Muscle Metabolism ◽  
Monocarboxylate Transporters ◽  
Rat Skeletal Muscle ◽  
Lactate Transport ◽  
Expression Of Genes ◽  
Sarcolemmal Vesicles ◽  
White Gastrocnemius

Triiodothyronine (T3) regulates the expression of genes involved in muscle metabolism. Therefore, we examined the effects of a 7-day T3 treatment on the monocarboxylate transporters (MCT)1 and MCT4 in heart and in red (RG) and white gastrocnemius muscle (WG). We also examined rates of lactate transport into giant sarcolemmal vesicles and the plasmalemmal MCT1 and MCT4 in these vesicles. Ingestion of T3 markedly increased circulating serum T3 ( P < 0.05) and reduced weight gain ( P < 0.05). T3 upregulated MCT1 mRNA (RG +77, WG +49, heart +114%, P < 0.05) and MCT4 mRNA (RG +300, WG +40%). However, only MCT4 protein expression was increased (RG +43, WG +49%), not MCT1 protein expression. No changes in MCT1 protein were observed in any tissue. T3 treatment doubled the rate of lactate transport when vesicles were exposed to 1 mM lactate ( P < 0.05). However, plasmalemmal MCT4 was only modestly increased (+13%, P < 0.05). We conclude that T3 1) regulates MCT4, but not MCT1, protein expression and 2) increases lactate transport rates. This latter effect is difficult to explain by the modest changes in plasmalemmal MCT4. We speculate that either the activity of sarcolemmal MCTs has been altered or else other MCTs in muscle may have been upregulated.

l(+)-Lactate transport perfused rat skeletal muscle: kinetic characteristics and sensitivity to pH and transport inhibitors

1988 ◽  
Vol 944 (2) ◽  
pp. 213-222 ◽  
Author(s):  
Peter W. Watt ◽  
Peter A. MacLennan ◽  
Harinder S. Hundal ◽  
Christy M. Kuret ◽  
Michael J. Rennie
Keyword(s):  
Skeletal Muscle ◽  
Kinetic Characteristics ◽  
Rat Skeletal Muscle ◽  
Lactate Transport ◽  
Transport Inhibitors

Vitamin E Concentration in Rat Skeletal Muscle and Liver after Exercise

1998 ◽  
Vol 8 (2) ◽  
pp. 105-112 ◽  
Author(s):  
Jon N. Swift ◽  
James P. Kehrer ◽  
K. Stephen Seiler ◽  
Joseph W. Starnes
Keyword(s):  
Skeletal Muscle ◽  
Vitamin E ◽  
High Performance ◽  
Time Course ◽  
Vastus Lateralis ◽  
Sprague Dawley ◽  
Rat Skeletal Muscle ◽  
Sedentary Control ◽  
Sprague Dawley Rats ◽  
Response To Exercise

The purpose of this study was to determine whether submaximal exercise significantly changes the concentration of vitamin E (αToc) in rat liver and skeletal muscle and to establish a time course for the return to basal levels. Male Sprague-Dawley rats, age 8 to 10 weeks, were randomly divided into sedentary control (Con) (n = 7) and exercise n = 17) groups. Exercised animals ran 100 min on a motorized treadmill at approximately 70% VO2max for 3 consecutive days. They were then sacrificed immediately postexercise (0Post), 24 hr post (24Post), or 72 hr post (72Post). The gastrocnemius, red vastus lateralis (RV), white vastus lateralis (WV), and liver were excised and analyzed for αToc concentration by high-performance liquid chromolography utilizing electrochemical detection. We found that after 3 consecutive days of exercise, αToc was reduced in RV and WV at 0Post and 24Post but returned to control values by 72Post. Liver αToc content was not changed at OPost but was significantly reduced at 24 Post and 72 Post. No significant changes in αToc were observed in the gastrocnemius in response to exercise. The data indicate that following an exercise-related decrease, skeletal muscle vitamin E concentration requires more than 24 hr to return to the preexercise concentration, and that the replenishment process may involve redistribution of vitamin E from liver to muscle.

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