Table 2

Glucuronidation activity in gastric microsomes

Substrate (100 μm1234
pmol/mg/min
1-Naphthol182.974.3299.371.8
4-Nitrophenol86.328.18120.264.8
4-Methylumbelliferone82.530.2129.162.4
4-Isopropylphenol31.88.229.525.2
Octyl-gallate35.316.22625.5
Estriol13.88.111.914.3
Estrone13.9512.916.9
Naringenin23.88.723.732.2
7-OH-benzo[α]pyrene33.59.32736.5
Hyodeoxycholic acid147.1N.D.N.D.N.D.

Gastric microsomal protein (25 μg) prepared from four individual gastric tissue specimens (1-4) were analyzed for glucuronidation activity as described in Materials and Methods. Sample 1 corresponds to Figure 3C, sample 2 to Figure 3B, sample 3 to Figure 3D, and sample 4 to Figure 3A. 14C-labeled glucuronides were separated by thin layer liquid chromatography and visualized after exposure to X-ray film. The glucuronides were scraped and quantified by liquid scintillation counting to determine specific catalytic activities. Only sample 1 exhibits catalytic activity toward hyodeoxycholic acid. The other specific activities vary 2- to 4-fold among the four samples, demonstrating a polymorphism of catalytic UGT activity in human gastric epithelium.

  • N.D., not detected.