Table 1.
Sulfating activities of human lung, liver, kidney, and small intestine cytosol fractions toward opioid drugs as substratesa)
| Substrate | Specific activity (pmol/min/mg) |
|||
|---|---|---|---|---|
| Lung | Liver | Kidney | Small Intestine | |
| Morphine | NDb) | 0.2 ± 0.1 | ND | ND |
| Hydromorphone | 6.3 ± 0.2 | 7.1 ± 1.1 | 3.2 ± 0.5 | 40.0 ± 0.7 |
| Oxymorphone | 3.7 ± 0.1 | 24.9 ± 0.9 | 5.5 ± 0.5 | 13.1 ± 0.9 |
| Butorphanol | ND | 1.3 ± 0.1 | ND | ND |
| Nalbuphine | ND | 0.3 ± 0.1 | ND | ND |
| Levorphanol | ND | 0.1 ± 0.1 | ND | ND |
| Nalorphine | 0.6 ± 0.1 | 3.7 ± 0.1 | 0.4 ± 0.1 | 3.6 ± 0.2 |
| Naltrexone | 2.5 ± 0.1 | 19.3 ± 0.2 | 1.5 ± 0.1 | 10.0 ± 0.3 |
| 6βNaltrexone | ND | 0.4 ± 0.2 | ND | ND |
a)
Specific activity refers to nmol substrate sulfated/min/mg purified enzyme. Data represent mean ± S.D. derived from three determinations. The concentration of the substrate used in the assay mixture was 50 µM.
b)
ND refers to activity not detected. Specific activity determined was lower than the detection limit (estimated to be ~0.1 pmol/min/mg protein).