Splanchnic removal of lactate and pyruvate during prolonged exercise in man

Rowell, L. B.; Kraning, Kenneth K.; Evans, T. O.; Kennedy, J. W.; Blackmon, John R.; Kusumi, F

doi:10.1152/jappl.1966.21.6.1773

Cited by 156 publications

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“…Hepatic blood flow was estimated by the continuous infusion technique (17) using indocyanine green dye (18). Leg blood flow was determined using the indicator dilution procedure described by Jorfeldt and Wahren (19).…”

Section: Methodsmentioning

confidence: 99%

Effect of protein ingestion on splanchnic and leg metabolism in normal man and in patients with diabetes mellitus.

Wahren¹,

Felig²,

Hagenfeldt³

1976

J. Clin. Invest.

355

138

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A B S T R A C T The inter-organ flux of substrates after a protein-rich meal was studied in seven healthy subjects and in eight patients with diabetes mellitus. Arterial concentrations as well as leg and splanchnic exchange of amino acids, carbohydate substrates, free fatty acids (FFA), and ketone bodies were examined in the basal state and for 3 h after the ingestion of lean beef (3 g/kg body wt). Insulin was withheld for 24 h before the study in the diabetic patients.In the normal subjects, after protein ingestion, there was a large amino acid release from the splanchnic bed predominantly involving the branched chain amino acids. Valine, isoleucine, and leucine accounted together for more than half of total splanchnic amino acid output. Large increments were seen in the arterial concentrations of the branched chain amino acids (100-200%) and to a smaller extent for other amino acids. Leg exchange of most amino acids reverted from a basal net output to a net uptake after protein feeding which was most marked for the branched chain amino acids. The latter accounted for more than half of total peripheral amino acid uptake. Alanine and glutamine were continuously taken up by the splanchnic tissues and released by the leg tissues after the protein meal, although This work was presented in part at the 67th Annual

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Section: Methodsmentioning

confidence: 99%

Effect of protein ingestion on splanchnic and leg metabolism in normal man and in patients with diabetes mellitus.

Wahren¹,

Felig²,

Hagenfeldt³

1976

J. Clin. Invest.

355

138

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“…INTRODUCTION The effect of intensive exercise (60% or more of maximum aerobic power [maximum 02 uptake]) on lactate metabolism has been well characterized. Such exercise results in increased production of lactate by exercising muscle (1), a rise in arterial lactate concentration (2, 3), and increased uptake of lactate by splanchnic tissues (4,5) and resting muscle (6). Less information is available regarding lactate metabolism during mild to moderate exercise (<60% maximum 02 uptake [VO2max])', which can be sustained for prolonged periods (1-3 h or more).…”

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confidence: 99%

Lactate and Glucose Exchange across the Forearm, Legs, and Splanchnic Bed during and after Prolonged Leg Exercise

Ahlborg¹,

Felig²

1982

J. Clin. Invest.

234

143

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A B S T R A C T The net exchange of glucose and lactate across the leg and the splanchnic bed and the arterialdeep venous (A-DV) differences for these substrates in the forearm were determined in healthy subjects during 3-3.5 h of leg exercise (bicycle ergometer) at 58% maximum 02 uptake and during a 40-min postexercise recovery period.Leg glucose uptake rose 16-fold during exercise and throughout the exercise period exceeded splanchnic glucose output. The latter reached a peak increment (3.5 times basal) at 90 min and fell by 60% during the third hour. As a result, blood glucose declined 40%, reaching frank hypoglycemia (blood glucose, <45 mg/ dl) in 50% of subjects at 3.5 h.Splanchnic lactate uptake rose progressively during exercise to values four times the basal rate at 3 h in association with a rise in arterial lactate to 1.5 mM. There was, however, no significant net output of lactate from the legs beyond 90 min of exercise. In contrast, the A-DV lactate difference in the forearm became progressively more negative throughout exercise, reaching values three times the basal level at 3.5 h. The rise in arterial lactate during exercise was proportional to the elevation in plasma epinephrine, which rose ninefold.During recovery, splanchnic lactate uptake rose further to values six times the basal rate, whereas lactate output by the legs was no greater than in the basal state. The A-DV lactate difference in the forearm became even more negative than during exercise, reaching values four times basal. During exercise as well as recovery, forearm uptake of blood glucose could ac- count for no more than 25-67% of forearm lactate release. Leg glucose uptake during recovery was threefold to fivefold higher than in the basal state in the face of plasma insulin concentrations that were 60% below basal and in association with a respiratory exchange ratio of 0.7.We conclude that (a) during prolonged leg exercise at 58% maximum 02 uptake an imbalance between splanchnic glucose production and leg glucose utilization results in a fall in blood glucose that may reach hypoglycemic levels in healthy subjects; (b) there is a marked increase in the uptake of lactate by the splanchnic bed that cannot be attributed to increased output of lactate from the exercising legs; (c) lactate is released by forearm muscle and, together with other relatively inactive muscle, may be an important source of the increased lactate turnover during and after prolonged leg exercise; (d) the increasingly negative A-DV lactate difference in the forearm cannot be accounted for by uptake of blood glucose, suggesting the breakdown of glycogen in forearm muscle during and after leg exercise; (e) increased glucose uptake by the legs in association with hypoinsulinemia during recovery suggests an increase in insulin sensitivity that permits glycogen repletion in previously exercising muscle in the absence of food ingestion; and (f) the evidence for increased lactate output in the forearm and augmented glucose uptake in the legs during recovery raises the pos...

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“…During exercise both active muscle (Stainsby & Welch, 1966;Freyschuss & Strandell, 1967;Karlsson, 1971a), and inactive muscle (Harris Bateman & Gloster, 1962;Keul, Doll & Keppler, 1967) utilize lactate. Other possible sites of lactate utilization during exercise include the heart (Carlsten, Hallgren, Jagenburg, Svanborg & Werk6, 1961;Olson, 1963), kidney cortex (Krebs, 1964;Krebs, Hems, Weidemanm & Speake, 1966;Levy, 1965) and liver (Kayne & Alpert, 1964;Rowell et al 1966).…”

Section: Discussionmentioning

confidence: 99%

“…Other workers have also reported a fall in blood lactate concentration following an initial rise when both moderate and severe exercise is continued beyond about 15 min (Tepperman & Tepperman, 1948;Astrand, Hallback, Hedman & Saltin, 1963;Rowell, Kraning, Evans, Kennedy, Blackmon & Kusami, 1966). Studies on isolated muscle also support an initial rapid production of lactate (Sacks, Sacks & Shaw, 1937;Flock, Ingle & Bollman, 1939).…”

Section: Introductionmentioning

confidence: 89%

The effect of exercise on lactate metabolism

Hubbard¹

1973

The Journal of Physiology

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SUMMARY1. An i.v. injection of 5 ,uc [U-14C]sodium L( + )-lactate was given to four subjects at rest and again 10 min after beginning a 40-50 min period of heavy exercise at an estimated 62-72 % of their maximum aerobic power (ro2 max.). Both blood lactate concentration and 102 remained relatively constant after the first few minutes of exercise.2. In all subjects both at rest and during exercise blood lactate and total radioactivity were measured at frequent intervals after injection of[14C]lactate. Timed expired gas collections were made and the quantity of 14C02 present in each collection measured. In two subjects the specific activity of lactate and of glucose isolated from blood was also measured.3. It was found that during 30 min of exercise 35-68 % of the administered [14C]lactate was recovered as 14C02 in the expired gas, whereas at rest only 3-7 % was recovered in the same period.4. After injection of ['40:]lactate the blood 14C concentration and the specific activity of the blood lactate declined very rapidly. This decline was more rapid during exercise than at rest.5. In the two subjects in whom it was measured the specific activity of blood glucose was lower during exercise than at rest.6. These results show that both at rest and during heavy exercise, lactate is removed from the blood and metabolized, and that during exercise this metabolism is much more rapid.7. In the light of these findings the sustained blood lactate concentration observed in these experiments is regarded as representing a dynamic equilibrium between the production and metabolism of lactate during exercise. The results give no support to the hypothesis that lactate is produced only during the first few minutes of submaximal work.

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Splanchnic removal of lactate and pyruvate during prolonged exercise in man

Cited by 156 publications

References 0 publications

Effect of protein ingestion on splanchnic and leg metabolism in normal man and in patients with diabetes mellitus.

Effect of protein ingestion on splanchnic and leg metabolism in normal man and in patients with diabetes mellitus.

Lactate and Glucose Exchange across the Forearm, Legs, and Splanchnic Bed during and after Prolonged Leg Exercise

The effect of exercise on lactate metabolism

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