A surrogate measure of whole body leucine transport across the cell membrane
| العنوان: | A surrogate measure of whole body leucine transport across the cell membrane |
|---|---|
| المؤلفون: | Anne Umpleby, Ian J. Gowrie, David Russell-Jones, Paul V. Carroll, Nicola Jackson, Roman Hovorka |
| المصدر: | American Journal of Physiology-Endocrinology and Metabolism. 276:E573-E579 |
| بيانات النشر: | American Physiological Society, 1999. |
| سنة النشر: | 1999 |
| مصطلحات موضوعية: | Adult, Male, medicine.medical_specialty, Physiology, Endocrinology, Diabetes and Metabolism, Coefficient of variation, Models, Biological, Cell membrane, Leucine, Physiology (medical), Internal medicine, medicine, Extracellular, Homeostasis, Humans, Leucine transport, Chemistry, Cell Membrane, Reproducibility of Results, Biological Transport, Membrane transport, Endocrinology, medicine.anatomical_structure, Female, Whole body, Intracellular |
| الوصف: | Based on a mass-balance model, a surrogate measure of the whole body leucine transport into and out of cells under steady-state conditions was calculated as u/ΔTTR, where u is the infusion rate of (stable label) leucine tracer and ΔTTR is the difference between the tracer-to-tracee ratio of extracellular and intracellular leucine. The approach was evaluated in ten healthy subjects [8 males and 2 females; age, 31 ± 9 (SD) yr; body mass index, 24.0 ± 1.6 kg/m2] who received a primed (7.58 μmol/kg) constant intravenous infusion (7.58 μmol ⋅ kg−1 ⋅ h−1) ofl-[1-13C]leucine over 180 min (7 subjects) or 240 min (3 subjects). Five subjects were studied on two occasions ≥1 wk apart to assess reproducibility. Blood samples taken during the last 30 min of the leucine infusion were used to determine plasma leucine concentration (129 ± 35 μmol/l), TTR of leucine (9.0 ± 1.5%), and TTR of α-ketoisocaproic acid (6.7 ± 0.8%). The latter TTR was taken as the measure of the free intracellular leucine TTR. The whole body inward and outward transport was 6.66 ± 3.82 μmol ⋅ kg−1 ⋅ min−1; the rate of leucine appearance due to proteolysis was 1.93 ± 0.24 μmol ⋅ kg−1 ⋅ min−1. A positive linear relationship between the inward transport and plasma leucine was observed ( P < 0.01), indicating the presence of the mass effect of leucine on its own transport. The transport was highly variable between subjects (between-subject coefficient of variation 57%) but reproducible (within-subject coefficient of variation 17%). We conclude that reproducible estimates of whole body transport of leucine across the cell membrane can be obtained under steady-state conditions with existing experimental and analytical procedures. |
| تدمد: | 1522-1555 0193-1849 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::38e6a4e0ab8f162d98b39733fcdf25dbTest https://doi.org/10.1152/ajpendo.1999.276.3.e573Test |
| رقم الانضمام: | edsair.doi.dedup.....38e6a4e0ab8f162d98b39733fcdf25db |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15221555 01931849 |
|---|