Table 1

Permeability of the marker molecules in the control period

MarkerMwRadius (Å)N1-fP × 103g (cm/hr)
[14C]-mannitol1843.91-a,  (3.4)1-b 40 /134.1  ± 0.35
[3H]-lactulose3435.11-a,  (4.8)1-b 6 /34.5  ± 0.79
[3H]-PEG 400∼4005.51-c,  (2.7)1-b 10 /44.5  ± 0.87
[3H]-PEG 900∼9008.01-c,  (8.4)1-d 9 /31.7  ± 0.31
[3H]-PEG 4000∼400015.91-c,  (16.4)1-d 6 /30.7  ± 0.07
[3H]-inulin∼500010.01-e,  (13.9)1-d 9 /42.1  ± 0.24
  • 1-a Estimated from Stokes-Einstein relationship with small-molecule correction reported by Steward, (1982), the value for lactulose is assumed to be similar to that for sucrose, a molecule similar in structure.

  • 1-b Based on smallest cross-sectional diameter determined by computer modeling, reported by Hollander et al. (1988).

  • 1-c Estimated from the relation D0 = 7 × 10−5 × Mw −0.46 = kT/6πηRH, where K is the Boltzmann constant, T = 298 K, the viscosity of water at 298 K is η = 0.000891 kg/msec (Handbook of Chemistry and Physics, 1988) and RH is the hydrodynamic radius (Johansson et al., 1991 a, b).

  • 1-d Measured by DLS in our laboratory.

  • 1-e Based on the radius of a cylindrical solvated molecule (Middleton, 1977).

  • 1-f N = number of tissues/number of animals.

  • 1-g Average values ± standard errors × 103.