Relationship between turnover rate and blood concentration of lactate in exercising dogs

1975 ◽  
Vol 39 (2) ◽  
pp. 231-234 ◽  
Author(s):  
F. L. Eldridge
Keyword(s):  
Steady State ◽  
Blood Lactate ◽  
Turnover Rate ◽  
The Other ◽  
Constant Infusion ◽  
Blood Concentrations ◽  
Lactate Turnover ◽  
Anesthetized Dogs ◽  
Lactate Removal ◽  
The Relationship

Steady-state blood lactate concentrationss and lactate turnover, or entry, rates were determined by use of constant infusion of L(+)-[14C]lactate in seven anesthetized dogs before and during electrically induced exercise. Lactate entry rates increased during exercise in all dogs with or without the infusion of additional exogenous cold lactate. Blood lactate concentrations, on the other hand, rose to levels considerably below those predicted for these entry rates in a previous study of the relationship in normal nonexercising dogs. It is concluded that improved efficiency of lactate removal during exercise allows low blood concentrations despite large increases in entry rates.

Enhanced efficiency of lactate removal after endurance training

1990 ◽  
Vol 68 (3) ◽  
pp. 1053-1058 ◽  
Author(s):  
C. M. Donovan ◽  
M. J. Pagliassotti
Keyword(s):  
Endurance Training ◽  
Blood Lactate ◽  
Specific Activity ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Consistent Difference ◽  
Blood Concentrations ◽  
Lactate Turnover ◽  
Lactate Removal ◽  
Lactate Infusion

The effects of endurance training (running 1 h/day at 40 m/min, 10% grade) on net lactate removal at various lactate concentrations were assessed in resting rats by use of constant exogenous lactate infusion (0, 69.3, 123.6, and 175.0 mumol.kg-1.min-1). No consistent difference in resting lactate concentrations, 1.17 +/- 0.09 mM, was observed between control and trained animals with no exogenous infusion of lactate. With increasing lactate infusion rates, control animals demonstrated a twofold greater increase in blood lactate concentration (range 1.2-11.4 mM) compared with trained animals (range 1.0-5.5 mM). This response resulted from a more rapid rise in net lactate removal with changes in blood lactate concentration for trained animals. The estimated maximal reaction velocity for net lactate removal in trained animals was 19% lower than in control animals; however, the Michaelis-Menten constant was greater than 66% lower in trained animals (4 mM) compared with controls (12 mM). Control animals also demonstrated a twofold greater increase in lactate concentration as a function of the tracer-estimated lactate turnover. The ratio of 14CO2 yield to lactate specific activity as a function of total tracer removal was not significantly different between groups, suggesting that the relative contributions of oxidation and gluconeogenesis to lactate removal were similar for both groups. At blood concentrations greater than 1 mM, trained animals achieve higher rates of lactate removal for any given lactate concentration.

Relationship of pyruvate and lactate during anaerobic metabolism. V: Coronary adequacy

1961 ◽  
Vol 200 (6) ◽  
pp. 1169-1176 ◽  
Author(s):  
William E. Huckabee
Keyword(s):  
Blood Flow ◽  
Coronary Flow ◽  
Cardiac Tissue ◽  
Anaerobic Metabolism ◽  
Constant Ratio ◽  
Blood Concentrations ◽  
Arterial Blood ◽  
Anesthetized Dogs ◽  
Relationship Of ◽  
The Relationship

Veno-arterial differences of pyruvate and lactate across the myocardium in chloralose-anesthetized dogs were very variable; in any one animal they changed continually with time despite constant blood flow and arterial blood concentrations. There was a systematic tendency of v-a lactate to vary with v-a pyruvate, as expressed in the calculated "Δ excess lactate," which remained nearly constant (or, if blood flow changed, bore a constant ratio to (a-v)O2). No change in Δ excess lactate from control values occurred in nonhypoxic experiments despite marked changes in v-a differences, arterial blood composition, and coronary flow. Cardiac Δ excess lactate became positive in most animals breathing 10% O2 in N2; output of excess lactate was also observed in all those in which moderate muscular exercise was induced. This anaerobic metabolism, or change in the relationship between pyruvate and lactate exchanges, was interpreted as an indication that O2 delivery response was not adequate to meet cardiac tissue requirements during such mild stresses when judged by the standards of adequacy of the basal state.

Blood Lactate Concentration and Clearance in Elite Swimmers During Competition

2011 ◽  
Vol 6 (1) ◽  
pp. 106-117 ◽  
Author(s):  
Jason D. Vescovi ◽  
Olesya Falenchuk ◽  
Greg D. Wells
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Active Recovery ◽  
Competitive Swimming ◽  
Elite Swimmers ◽  
Lactate Removal ◽  
The Relationship ◽  
Competitive Swimmers ◽  
Effect Of Age

Purpose:Blood lactate concentration, [BLa], after swimming events might be influenced by demographic features and characteristics of the swim race, whereas active recovery enhances blood lactate removal. Our aims were to (1) examine how sex, age, race distance, and swim stroke influenced [BLa] after competitive swimming events and (2) develop a practical model based on recovery swim distance to optimize blood lactate removal.Methods:We retrospectively analyzed postrace [BLa] from 100 swimmers who competed in the finals at the Canadian Swim Championships. [BLa] was also assessed repeatedly during the active recovery. Generalized estimating equations were used to evaluate the relationship between postrace [BLa] with independent variables.Results:Postrace [BLa] was highest following 100–200 m events and lowest after 50 and 1500 m races. A sex effect for postrace [BLa] was observed only for freestyle events. There was a negligible effect of age on postrace [BLa]. A model was developed to estimate an expected change in [BLa] during active recovery (male = 0; female = 1): [BLa] change after active recovery = –3.374 + (1.162 × sex) + (0.789 × postrace [BLa]) + (0.003 × active recovery distance).Conclusions:These findings indicate that swimmers competing at an elite standard display similar postrace [BLa] and that there is little effect of age on postrace [BLa] in competitive swimmers aged 14 to 29 y.

Mammalian metabolite flux rates in a teleost: lactate and glucose turnover in tuna

1986 ◽  
Vol 250 (3) ◽  
pp. R452-R458 ◽  
Author(s):  
J. M. Weber ◽  
R. W. Brill ◽  
P. W. Hochachka
Keyword(s):  
Blood Lactate ◽  
Turnover Rate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Lactate Clearance ◽  
Glucose Turnover ◽  
Skipjack Tuna ◽  
Turnover Rates ◽  
Total Blood ◽  
Lactate Turnover

Lactate and glucose turnover rates were measured by bolus injection of [U-14C]lactate and [6-3H]glucose in cannulated lightly anesthetized skipjack tuna, Katsuwonus pelamis. Our goals were to find out whether the high rates of lactate clearance reported during recovery from burst swimming in tuna could be accounted for by high blood lactate fluxes; to extend the observed correlation between lactate turnover and lactate concentration in mammals to a nonmammalian system, and to assess the importance of lactate and glucose as metabolic fuels in tuna and to compare their flux rates with values reported for mammals. Measured lactate turnover rates ranged from 112 to 431 mumol X min-1 X kg-1 and were correlated with blood lactate concentration. Glucose turnover rate averaged 15.3 mumol X min-1 X kg-1. When correcting for body mass and temperature, skipjack tuna has at least as high or even higher lactate turnover rates than those recorded for mammals. Tuna glucose turnover rate is similar to that of mammals but much higher than levels found in other teleosts. Even the highest lactate turnover rate measured in tuna cannot fully account for the rate of blood lactate clearance observed during recovery, suggesting that some of the lactate produced in skeletal muscle must be metabolized in situ. After injection of [U-14C]lactate, less than 5% of the total blood activity was recovered in glucose, suggesting that the Cori cycle is not an important pathway of lactate metabolism in tuna.

ON THE RELATIONSHIP BETWEEN TESTICULAR BLOOD FLOW AND SECRETION OF TESTOSTERONE IN ANESTHETIZED DOGS STIMULATED WITH HUMAN CHORIONIC GONADOTROPHIN

1964 ◽  
Vol 42 (5) ◽  
pp. 671-677 ◽  
Author(s):  
Kristen B. Eik-Nes
Keyword(s):  
Blood Flow ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Arterial Blood Flow ◽  
Constant Infusion ◽  
Left Testis ◽  
Arterial Blood ◽  
Constant Rate ◽  
Anesthetized Dogs ◽  
The Relationship

The concentration of testosterone has been measured in spermatic vein blood from the left testis in 25 anesthetized dogs, stimulated with human chorionic gonadotrophin and infused with arterial blood via the left spermatic artery at different rates. The secretion of testosterone varied with the rate at which arterial blood was infused and at a constant infusion rate of 3.81 ml/min, animals weighing from 19 to 23 kg produced testosterone at a constant rate over 90 minutes. Infusion rates lower than this decreased the secretion of testosterone, and if arterial blood was infused at a rate of 0.76 ml/min for the first 30 minutes of experimentation, the capacity of the infused testis to secrete testosterone in the ensuing 60 minutes was impaired even in animals given large doses of human chorionic gonadotrophin via the left spermatic artery. A relationship between the arterial blood flow to the testis and its ability to secrete testosterone under the influence of human chorionic gonadotrophin is thus established.

Changes in glycerol kinetics after E. coli endotoxin administration in dogs

1984 ◽  
Vol 246 (3) ◽  
pp. R325-R330
Author(s):  
O. P. McGuinness ◽  
J. J. Spitzer
Keyword(s):  
Steady State ◽  
Infusion Rate ◽  
Volume Of Distribution ◽  
Constant Infusion ◽  
Metabolic Clearance ◽  
Glycerol Concentration ◽  
Endotoxin Administration ◽  
E Coli ◽  
The Face ◽  
Anesthetized Dogs

The metabolic clearance rate (MCR) and maximal rate of glycerol removal (Rd max) were determined in anesthetized dogs at two time periods after the intravenous administration of either Escherichia coli endotoxin or saline. The nonisotopic method employed in these studies to determine the MCR of glycerol consisted of a constant infusion of glycerol at three different infusion rates. At each infusion rate a steady-state glycerol concentration was obtained. The reciprocal of the slope of the linear relationship between the glycerol infusion rate and the change in the steady-state arterial glycerol concentration was equal to the MCR of glycerol. Administration of endotoxin significantly decreased the MCR of glycerol, whereas the volume of distribution of glycerol was not altered significantly. The arterial glycerol turnover remained unaltered, whereas arterial glycerol concentration increased after endotoxin administration. The studies demonstrate that the elevated arterial glycerol concentration maintained the rate of glycerol turnover in the face of decreased efficiency of glycerol removal after endotoxin administration.

Renal concentrating operation in hypothermic dogs

1959 ◽  
Vol 196 (5) ◽  
pp. 1150-1154 ◽  
Author(s):  
Suk Ki Hong ◽  
John W. Boylan
Keyword(s):  
Steady State ◽  
Body Temperature ◽  
Isotonic Saline ◽  
Free Water ◽  
Tubular Reabsorption ◽  
Urine Flow ◽  
Constant Infusion ◽  
Threefold Increase ◽  
Anesthetized Dogs ◽  
Ice Water

The renal concentrating operation during hydropenia and during constant infusion of 2 m urea in isotonic saline was studied in 10 anesthetized dogs. PAH, exogenous creatinine and osmolal clearances were determined, as well as rates of Na and Cl excretion. Following two to four control periods body temperature was lowered to approximately 25°C by the use of an ice-water bath. The above measurements were then repeated during this steady state of hypothermia. PAH and creatinine clearances are reduced to approximately one-third of control values, while urine flow is not significantly changed. Thus, proportionately less filtered water is reabsorbed. Osmolal clearance is reduced, but this reduction is less than that of GFR so that a decrease in the tubular reabsorption of filtered osmotic particles occurs in hypothermia. This reduction in tubular reabsorption of solute is revealed further in a two to threefold increase in the percentage excretion of filtered NaCl and total osmotic substance. A greater decrease in the process which removes free water (TcHH2O) from the supposedly isotonic tubular fluid results in a reduction to one-third to one-fourth of the control values for TcHH2O. There would appear to be a dissociation of water and solute reabsorptions in hypothermia which indicates a decrease in the renal concentrating process.

Carbon dioxide transport in anesthetized dogs during inhibition of carbonic anhydrase

1961 ◽  
Vol 16 (6) ◽  
pp. 1023-1028 ◽  
Author(s):  
Stephen M. Cain ◽  
Arthur B. Otis
Keyword(s):  
Carbon Dioxide ◽  
Steady State ◽  
Carbonic Anhydrase ◽  
The Other ◽  
Pure Oxygen ◽  
Carbon Dioxide Transport ◽  
Carbon Dioxide Output ◽  
Initial Control ◽  
Anesthetized Dogs ◽  
Mixed Venous

Following inhibition of blood carbonic anhydrase by acetazolamide in anesthetized dogs with one lung rebreathing in connection with a bag and with the other lung ventilating freely on pure oxygen, mixed venous Pco2 increased and alveolar Pco2 decreased. Carbon dioxide output dropped initially but gradually rose and attained a steady state value equal to that of the initial control condition. Before acetazolamide, 19% of the pulmonary CO22 output was derived from dissolved CO2, 26% from carbamino compound, and 55% from bicarbonate. In the new steady state following acetazolamide, 45% came from dissolved CO2, 38% from carbamino, and 17% from bicarbonate. Submitted on June 12, 1961

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