ABSTRACT
Objective:To measure the kinetic parameters of murine plasma albumin synthesis by deuterated water (2H2O).Methods:Twenty SD rats received 2H2O-labelled intraperitoneal injection and drinking.At the end of the 1st,3rd,5th,6th,10th week,every 4 rats was respectively sacrificed by cardiac puncture for blood collection.Plasma albumin was purified by trichloroacetic acid and ethanol,identified by SDS-PAGE and hydrolyzed by hydrochloric acid.The alanine in albumin and plasma was separated,purified and derived.The deuterium enrichments of alanyl unit in albumin and alanine in plasma were determined by GC-MS.The fractional synthesis rate of albumin and synthetic dynamic equation were calculated.Results:The fractional synthesis rate of plasma albumin was 15.3％/w,and synthetic dynamic equation was ft =1.256 × (1-e-0.153t).Conclusion:The kinetic parameters of plasma albumin synthesis can be measured by 2H2O labeling method,which can be applied in the study of physiological and pathological metabolic mechanism.
ABSTRACT
The aim of the present study was to measure the kinetic parameters of skeletal muscle protein synthesis in rats by deuterated water (HO). Twenty Sprague-Dawley (SD) rats were labeled byHO through intraperitoneal injection and drinking. At the each end of the 1st, 3rd, 5th, 6th and 10th week after the firstHO labeling, four rats were sacrificed by cardiac puncture for blood plasma and quadriceps femoris sampling. Skeletal muscle protein and free amino acids in plasma were purified, hydrolyzed by hydrochloric acid and derived. The deuterium enrichments ofH-labeled alanyl in skeletal muscle protein and plasma protein-boundH-labeled alanine were determined by gas chromatography-mass spectrometry (GC-MS). The fractional synthesis rate of skeletal muscle protein and synthetic dynamic equation were calculated. The fractional synthetic rate of skeletal muscle protein was 12.8%/week, and synthetic dynamic equation was f= 0.158 × (1 - e). The results suggest that the kinetic parameters of skeletal muscle protein synthesis can be measured byHO labeling, and the method can be applied in long-term labeling experiment.