Lactate influx into red blood cells from trained and untrained human subjects

• Published in: Medicine and science in sports and exercise Vol. 30; no. 4; pp. 536 - 542
• Main Authors: SKELTON, M. S, KREMER, D. E, SMITH, E. W, GLADDEN, L. B
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01-04-1998
• Subjects: Adult; Biological and medical sciences; Biological Transport - physiology; Erythrocytes - chemistry; Exercise - physiology; Fundamental and applied biological sciences. Psychology; Humans; Lactic Acid - metabolism; Male; Oxygen Consumption - physiology; Physical Fitness - physiology; Space life sciences; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Human; Lactates; Blood cell; Energy metabolism; Physical training; Membrane transport; Biological transport; Plasma membrane; Red blood cell
• ISSN: 0195-9131; 1530-0315
• DOI: 10.1097/00005768-199804000-00011

The purpose of this study was to compare the fractional contributions of the three pathways of lactate transport (band 3 system, nonionic diffusion, and monocarboxylate pathway) into red blood cells (RBC) from trained and untrained humans.
Blood samples were obtained from 19 male subjects: 5 untrained, 5 aerobically-trained, 5 competitive collegiate cross-country runners, and 4 competitive collegiate sprinters. The influx of lactate into the RBC was measured by a radioactive tracer technique using [14C]lactate. Discrimination of each pathway of lactate transport was achieved by using PCMBS (1 mM) to block the monocarboxylate pathway and DIDS (0.2 mM) to block the band 3 system. Nonionic diffusion was calculated as the difference between total lactate influx and the sum of band 3 and monocarboxylate lactate influx.
Total lactate influx into the RBC from the more aerobic individuals (trained subjects and cross-country runners) was significantly faster at 1.6 mM lactate concentration ([La]) as compared with the influx into RBC of the untrained subjects. Total influx of lactate was significantly higher (P < 0.05) in the RBC from the sprinters as compared with that in the RBC from the untrained subjects at 41 mM [La]. There were no significant differences among the four groups with regard to the total influx of lactate at 4.1, 8.1, and 20 mM [La]. In general, the percentage of total lactate influx accounted for by each of the three parallel pathways at 1.6, 8.1, and 41.0 mM [La] was not different among the four groups of subjects.
Overall, the groups were more similar than different with regard to RBC lactate influx.