Table 2

Time course of induction of midazolam hydroxylation activity in Caco-2 cells after treatment with 19-nor-1,25-D2 or 1,25-D3

Treatment1′-OH-MDZ Formation Rate (pmol/hr/insert)2-a
19-nor-1,25-D2 (0.1 μM)1,25-D3 (0.1 μM)19-nor-1,25-D2 (1.0 μM)1,25-D3 (1.0 μM)
day
0BldBldBldBld
3Bld1.342-b 8.002-b 7.90  ± 3.20
72.44  ± 1.665.25  ± 0.3924.1  ± 3.621.3  ± 1.46
1510.0  ± 1.462-c 18.7  ± 3.054.6  ± 11.144.9  ± 4.70
219.52  ± 0.402-c 21.4  ± 1.1366.6  ± 14.070.5  ± 5.90
  • 2-a  Product formation rate (mean ± SD for triplicate incubations) following application of a single 2 μM dose of midazolam to the apical compartment. 1′-OH MDZ formation was below limit of detection in cells treated with vehicle for 3 to 21 days.

  • 2-b  Quantifiable rate for one of three incubations.

  • 2-c  Significantly different from 1,25-D3 effect at equivalent dose, p < 0.001.

  • Bld, below limit of detection.