Table 2

Parameters obtained from the literature (Pang et al., 1991) or scaled up from data of in vitro studies

ParameterDescriptionValue
C in(μM)Initial input concentration of enalapril2.52-a
fu, ft Unbound fraction in sinusoid or tissue0.822-a
Q (ml/min)Plasma flow rate = [blood flow rate × (1 − hematocrit)]10.32-a
Liver weight (g)Weight of whole liver12.82-a
V max uptake (nmol/min/g liver)Maximal velocity for uptake in all zones1377  ± 1862-b
K m uptake(μM)Michaelis-Menten constant for uptake in all zones344  ± 522-b
PSin (ml/min/g)Influx permeability surface area product4.0
V max,PP met (nmol/min/g liver)Maximal velocity of metabolism in periportal zone547  ± 3102-b
K m,PP met(μM)Michaelis-Menten constant for metabolism in periportal zone1049  ± 3352-b
CLint,PP met (ml/min/g)Metabolic intrinsic clearance in periportal region0.52  ± 0.34
V max,MZ met (nmol/min/g liver)Maximal velocity of metabolism in midzonal region805  ± 3002-b
K m,MZ met(μM)Michaelis-Menten constant for metabolism in midzonal region1308  ± 4192-b
CLint,MZ met (ml/min/g)Metabolic intrinsic clearance in midzonal region0.62  ± 0.30
V max,PV met (nmol/min/g liver)Maximal velocity of metabolism in perivenous zone2096  ± 6002-b
K m,PV met(μM)Michaelis-Menten constant for metabolism in perivenous zone2612  ± 2362-b
CLint,PV met (ml/min/g)Metabolic intrinsic clearance in perivenous region0.80  ± 0.24
CLint,liver met(ml/min)2-c Metabolic intrinsic clearance for whole liver8.27
CLint,liver bile(ml/min)2-d Biliary intrinsic clearance for whole liver0.408
CLint,liver total(ml/min)2-e Total intrinsic clearance for whole liver8.68

  • ↵2-a Values from Pang et al., 1991.

  • ↵2-b Mean ± S.D. (n = 4) of in vitro parameters that were scaled up to whole organ level using the factors of Mahler and Cordes (1996).

  • ↵2-c According to eq. 8.

  • ↵2-d According to eq. 9.

  • ↵2-e According to eq. 10.