Organelle marker enzyme activities in rat jejunum
| Organelle | Marker | Control | One hour | Six hours | Twenty hours |
| Nucleus | DNA (mg/g tissue) | 4.3 (0.8) | 4.0 (0.3) | 4.0 (0.6) | 3.7 (0.5)** |
| Brush border | Alkakine phosphatase (mU/mg DNA) | 838 (98) | 564 (138)** | 432 (85)** | 598 (187)** |
| Cytosol | Lactate dehydrogenase (U/mg DNA) | 79 (29) | 48 (14) | 56 (21) | 83 (16) |
| Lysosomes | N-Acetyl glucosaminidase (mU/mg DNA) | 135 (41) | 125 (44) | 151 (40) | 155 (39) |
| Endoplasmic reticulum | α-Glucosidase (U/mg DNA) | 2.3 (0.2) | 2.2 (0.2) | 2.7 (0.5) | 3.3 (0.7) |
| Mitochondria | Succinate dehydrogenase (mU/mg DNA) | 102 (18) | 168 (61)** | 178 (31)** | 322 (48)** |
| Cytochrome c oxidase (velocity: Kmin/mg protein) | 0.20 (0.04) | 0.32 (0.11)** | 0.25 (0.07) | 0.19 (0.03) | |
| Citrate synthase (μM/min/mg protein) | 1.68 (0.69) | 3.05 (0.44)** | 3.58 (0.45)** | 2.83 (0.52)** |
Sprague-Dawley rats (eight to 24 in each group) received indomethacin (30 mg/kg) by gavage and were killed one, six, or 20 hours later.
The results show significantly (**p<0.01, Wilcoxon’s rank sum test) lower DNA levels at 20 hours possibly because of a reduction in cell numbers as a result of ulceration. Alkaline phosphatase activities (brush border marker) are significantly reduced throughout which could represent direct damage by NSAIDs or inactivation due to oxygen reactive metabolites.31 There are significant increases in the three mitochrondial marker enzyme activities at one hour, albeit transient in the case of cytochrome c oxidase.