L3,2and L2,3. Table 2.2 compares the com-
partment masses and mass transfer rates
between compartments for each species.
Also listed is the de novoproduction rate
Measurement and Significance of Protein Turnover 41
Tracer
(A) Cattle, dog and human model
1
Extracellular
fluid
2
Tissue
pool
3
Tissue
pool
Urine 3MH
Skeletal
muscle
de
novo
Tracer
(B) Sheep model
Extracellular
fluid
Tissue
pool
Tissue
pool
Urine 3MH
Skeletal
muscle
de
novo
Balenine
Tracer
(C) Swine model
1
Extracellular
fluid
2
Tissue
pool
3
Tissue
pool
Skeletal
muscle
de
novo
Balenine
Fig. 2.11.Schematic of the three-compartment models used to analyse the kinetics of distribution, metabolism
and de novoproduction of 3-methylhistidine (3MH). The tracer, 3-[^2 H 3 -methyl]methylhistidine (D 3 -3MH), was
injected into compartment 1. Sampling was performed from compartment 1. De novoproduction of 3MH
and the exit from the system are dependent on the physiology of the species.