Lactate transport studied in sarcolemmal giant vesicles from rats: effect of training

1993 ◽  
Vol 264 (2) ◽  
pp. E156-E160 ◽  
Author(s):  
H. Pilegaard ◽  
C. Juel ◽  
F. Wibrand

The effect of training on lactate transport capacity was studied in giant vesicles obtained with collagenase treatment of rat skeletal muscles. Marker enzyme analyses demonstrated that these vesicles are predominantly of sarcolemmal origin. Treadmill training induced significant adaptations in the capacity of rat skeletal muscles to transport lactate but swimming [low-intensity training, approximately 50% of maximal oxygen consumption (VO2 max)] did not. After 7 wk of moderate (90% of VO2max)- and high-intensity (112% of VO2max) interval treadmill training the carrier-mediated equilibrium exchange flux with 30 mM lactate was increased by 58 and 76%, respectively. During 5 wk of detraining the capacity to transport lactate decreased to near control level. It is concluded that physical training can increase the capacity to transport lactate in rat skeletal muscles and that the training intensity is of great importance. The adaptation appears to include both an increased number of transport proteins and a higher affinity of the individual transporters.

1994 ◽  
Vol 76 (3) ◽  
pp. 1031-1036 ◽  
Author(s):  
C. Juel ◽  
S. Kristiansen ◽  
H. Pilegaard ◽  
J. Wojtaszewski ◽  
E. A. Richter

We developed a method that allows the measurement of muscle lactate transport in humans. The transport studies were carried out with giant (1.8- to 36-microns-diam) sarcolemmal vesicles obtained by collagenase treatment of needle biopsy material. Marker enzyme analyses demonstrated that the vesicular membrane is predominantly of sarcolemmal origin, contamination with sarcoplasmic reticulum membranes is very low, and mitochondrial membranes are not a major contaminant. The vesicles were loaded with labeled lactate, and the efflux was measured. The system displayed saturation kinetics and inhibitor sensitivity. In equilibrium exchange experiments (pH 7.4, 21 degrees C), the Michaelis-Menten constant (Km) for the carrier-mediated flux was 30 +/- 8 (SD) mM and maximal transport rate (Vmax) was 184 +/- 24 pmol.cm-2.s-1 (142 nmol.mg protein-1.min-1). In zero-trans efflux experiments, Km was 24 +/- 8 mM and Vmax was 81 +/- 11 pmol.cm-2.s-1 (63 nmol.mg protein-1.min-1). In infinite-cis experiments with a variable lactate concentration on the outside of the vesicles, Km was 8 +/- 4 mM and Vmax was 136 +/- 9 pmol.cm-2.s-1 (105 nmol.mg protein-1.min-1). Thus, the system displayed transacceleration. Low pH (6.4) had no significant effect on equilibrium exchange experiments, whereas in zero-trans experiments low pH at the trans side inhibited the flux by 50%. We concluded that lactate transport can be studied in giant vesicles obtained from a single human muscle biopsy. Our data provide evidence for the existence of a lactate carrier in human sarcolemma. This transport system must be taken into account in models of human lactate kinetics.


1995 ◽  
Vol 269 (4) ◽  
pp. E679-E682 ◽  
Author(s):  
H. Pilegaard ◽  
C. Juel

The effect of denervation on lactate transport capacity was studied in giant sarcolemmal vesicles obtained from rat muscle. The rate of lactate transport was determined in soleus and red (RG) and white gastrocnemius (WG) after 1, 3, and 21 days of denervation and in the corresponding contralateral muscles. In addition, muscle lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) activities were determined. After 1, 3, and 21 days of denervation the rate of lactate transport was lower (P < 0.05) in WG (9, 11, and 36%), RG (15, 21, and 41%), and soleus (12, 24, and 50%) compared with the contralateral muscles. After 21 days of denervation LDH activity was 26, 25, and 34% and SDH activity 33, 25, and 27% lower (P < 0.05) in WG, RG, and soleus, respectively, compared with the contralateral muscles. In the control muscles the lactate transport capacity was 20 and 32% lower (P < 0.05) in WG than in RG and soleus, respectively. The present findings provide support that the sarcolemmal lactate carrier is a plastic system; the transport capacity in soleus, RG, and WG already declines after 1 day of denervation and is further reduced after 21 days of denervation. In addition, the data suggest that the lactate transport capacity in fast-twitch glycolytic fibers < fast-twitch oxidative-glycolytic fibers < slow-twitch oxidative fibers.


1958 ◽  
Vol s3-99 (48) ◽  
pp. 469-473
Author(s):  
J. C. GEORGE ◽  
K. S. SCARIA

Certain dehydrogenases in the breast muscle of the pigeon and fowl and the leg muscle of the fowl and frog were studied histochemically by the use of 2:3:5: triphenyl tetrazolium chloride. The dehydrogenase activity was found to have a relationship with the colour and the mitochondrial content of the individual muscle fibres. In the pigeon breast muscle, however, the broad white fibres did not show the presence of any of the enzymes studied. It is therefore concluded that these fibres in the pigeon breast muscle are a unique system in which none of the oxidative processes concerned takes place; they cannot be considered as analogous to the white fibres of the other muscles studied.


1950 ◽  
Vol 92 (2) ◽  
pp. 169-190 ◽  
Author(s):  
Alwin M. Pappenheimer ◽  
Joan B. Daniels ◽  
F. S. Cheever ◽  
T. H. Weller

A study has been made of the lesions produced in suckling mice by the following viruses: Powers, Matulaitis, DeMole, Kine, McCarthy, Conn. 5, Ohio R, High Point, WS No. 4, EMC, and Col. SK. Pathologic alterations have been found in myocardium, lungs, liver, pancreas, thymus, brain and spinal cord, adipose tissue, and skeletal muscles. A comparison of the lesions produced by the individual strains has disclosed certain differential features which are discussed in detail. Within the group of so called Coxsackie viruses, myositis has not proved to be a constant finding, and it may occur in suckling mice infected with other types of virus.


1961 ◽  
Vol 16 (3) ◽  
pp. 557-561 ◽  
Author(s):  
Newton B. Everett ◽  
Lorna Matson

Red cell and plasma volumes of the total rat and of its individual tissues and organs were determined for animals exposed to 5 C for 4 hr, 24 hr, 2 weeks, and 6 weeks. In addition, the tissue hematocrit ratios were determined. These values were compared with those of rats kept at 24 C. Fe59-labeled erythrocytes and I131-labeled albumin were given intravenously, and after mixing the rats were frozen in liquid nitrogen. The organs and tissues were removed in the frozen state, assayed for radioactivity, and blood cell and plasma volumes were calculated on a unit weight basis. Significant changes in blood cell and plasma volumes were observed for the total rat and for many of the individual organs. There was a significant increase in the red cell content of the total rat within 24 hr of cold exposure. After 6 weeks, total blood volume was increased by approximately 20% over the control level and the increase in erythrocyte volume was slightly more than the increase in plasma volume. The hematocrit ratio of heart blood was 44.8 after 6 weeks exposure compared with 41.5 for controls. In general, it can be said that the somatic parts of the body showed increases in blood volume whereas the visceral parts had decreased volumes. Submitted on August 15, 1960


1998 ◽  
Vol 274 (3) ◽  
pp. E554-E559 ◽  
Author(s):  
Henriette Pilegaard ◽  
Sven Asp

The effect of prior eccentric contractions on skeletal muscle lactate/H+transport was investigated in rats. Lactate transport was measured in sarcolemmal giant vesicles obtained from soleus and red (RG) and white gastrocnemii (WG) muscles 2 days after intense eccentric contractions (ECC) and from the corresponding contralateral control (CON) muscles. The physiochemical buffer capacity was determined in the three muscle types from both ECC and CON legs. Furthermore, the effect of prior eccentric contractions on release and muscle content of lactate and H+ during and after supramaximal stimulation was examined using the perfused rat hindlimb preparation. The lactate transport rate was lower ( P < 0.05) in vesicles obtained from ECC-WG (29%) and ECC-RG (13%) than in vesicles from the CON muscles. The physiochemical buffer capacity was reduced ( P < 0.05) in ECC-WG (13%) and ECC-RG (9%) compared with the corresponding CON muscles. There were only marginal effects on the soleus muscle. Muscle lactate concentrations and release of lactate during recovery from intense isometric contractions were lower ( P< 0.05) in ECC than in CON hindlimbs, indicating decreased anaerobic glycogenolysis. In conclusion, the sarcolemmal lactate/H+ transport capacity and the physiochemical buffer capacity were reduced in prior eccentrically stimulated WG and RG in rats, suggesting that muscle pH regulation may be impaired after unaccustomed eccentric exercise. In addition, the data indicate that the glycogenolytic potential is decreased in muscles exposed to prior eccentric contractions.


1999 ◽  
Vol 79 (5) ◽  
pp. 391-396 ◽  
Author(s):  
M. L. Zonderland ◽  
P. R. B�r ◽  
J. C. Reijneveld ◽  
B. M. Spruijt ◽  
H. A. Keizer ◽  
...  

2004 ◽  
Vol 96 (6) ◽  
pp. 2257-2264 ◽  
Author(s):  
Russell T. Hepple ◽  
Janis E. Vogell

The anatomic size of the capillary-to-fiber (C/F) interface plays an important role in O2 flux from blood to tissue by determining the surface area available for diffusion and is maintained in relative proportion to fiber mitochondrial volume across a wide range of muscle aerobic capacity. In the present study, we examined an estimate of the anatomic size of the C/F interface [the quotient of the individual C/F ratio and fiber perimeter, C/F perimeter exchange (CFPE) index] and fiber oxidative capacity in different skeletal muscles, or muscle regions, to test the hypothesis that capillarization would be maintained in relative excess of reduced fiber oxidative capacity in aged muscles. The right gastrocnemius, plantaris, and soleus muscles from young adult (8 mo old) and late middle-aged (28–30 mo old) Fischer 344 × Brown Norway F1 hybrid rats were excised for evaluation of flux through electron transport chain complexes I–III and/or morphometric estimation of capillarization. Muscle mass was lower in the gastrocnemius muscles of the older animals (2,076 ± 32 vs. 1,825 ± 47 mg in young adult vs. late middle-aged, respectively; mean ± SE) but not the plantaris or soleus muscles. Fibers were smaller in the white region of gastrocnemius muscles but larger in the red region of gastrocnemius muscles of the older animals. There was no difference in the number of capillaries around a fiber, the individual C/F ratio, or the CFPE index between groups for any muscle/region, whereas flux through complexes I–III was reduced by 29–43% in late middle-aged animals. Thus the greater quotient of indexes of anatomic capillarity (individual C/F ratio or CFPE index) and fiber oxidative capacity in soleus and the white region of gastrocnemius muscles, but not in the red region of gastrocnemius muscles of the older animals, shows that anatomic capillarity is maintained in relative excess of oxidative capacity in some muscle regions in late middle-aged rats.


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