TY - JOUR

T1 - Ammonia uptake in inactive muscles during exercise in humans

AU - Bangsbo, Jens

AU - Kiens, Bente

AU - Richter, Erik A.

PY - 1996

Y1 - 1996

N2 - The present study examined NH3 (ammonia and ammonium) uptake in resting leg muscle. Six male subjects performed intermittent arm exercise at various intensities in two separate 32-min periods (part I and part II) and in one subsequent 20-min period in which one-legged exercise was also performed (part III). The arterial plasma NH3 concentration was 79.6 +/- 9.6 (SE) mumol/l at rest and 88.1 +/- 9.1, 98.1 +/- 8.1, and 210.2 +/- 7.5 mumol/l after 10 min of exercise in parts I, II, and III, respectively. The corresponding NH3 uptakes in the resting leg were 3.3 +/- 1.3 (rest), 7.8 +/- 1.5, 14.0 +/- 4.5, and 57.7 +/- 18.3 mumol/min. Throughout each exercise period a net uptake of NH3 was observed in the resting leg (P < 0.05), but uptake decreased to resting values within 5 min of termination of exercise. The muscle NH3 concentration of 195.1 +/- 15.0 mumol/kg wet wt at rest was largely unchanged throughout the experiment. The present data suggest that resting muscles extract NH3 and contribute significantly to clearance of NH3 during exercise and in early recovery from exercise. The extracted NH3 appears to be metabolized within the resting muscles.

AB - The present study examined NH3 (ammonia and ammonium) uptake in resting leg muscle. Six male subjects performed intermittent arm exercise at various intensities in two separate 32-min periods (part I and part II) and in one subsequent 20-min period in which one-legged exercise was also performed (part III). The arterial plasma NH3 concentration was 79.6 +/- 9.6 (SE) mumol/l at rest and 88.1 +/- 9.1, 98.1 +/- 8.1, and 210.2 +/- 7.5 mumol/l after 10 min of exercise in parts I, II, and III, respectively. The corresponding NH3 uptakes in the resting leg were 3.3 +/- 1.3 (rest), 7.8 +/- 1.5, 14.0 +/- 4.5, and 57.7 +/- 18.3 mumol/min. Throughout each exercise period a net uptake of NH3 was observed in the resting leg (P < 0.05), but uptake decreased to resting values within 5 min of termination of exercise. The muscle NH3 concentration of 195.1 +/- 15.0 mumol/kg wet wt at rest was largely unchanged throughout the experiment. The present data suggest that resting muscles extract NH3 and contribute significantly to clearance of NH3 during exercise and in early recovery from exercise. The extracted NH3 appears to be metabolized within the resting muscles.

KW - Adult

KW - Ammonia

KW - Arm

KW - Arteries

KW - Homeostasis

KW - Humans

KW - Hydrogen-Ion Concentration

KW - Leg

KW - Male

KW - Muscle, Skeletal

KW - Osmolar Concentration

KW - Physical Exertion

KW - Potassium

KW - Regional Blood Flow

KW - Rest

M3 - Journal article

C2 - 8772481

VL - 270

SP - E101-E106

JO - American Journal of Physiology - Endocrinology and Metabolism

JF - American Journal of Physiology - Endocrinology and Metabolism

SN - 0193-1849

IS - 1

ER -