RESUMO
The purpose of this study is to investigate the factors that cause malformed frogs in upstream Kaoping river (KP site) and Tungkang river (T site) of Southern Taiwan. In this experiment, the activities of monooxygenase (MO), glutathione-S-transferase (GST), acetylcholinesterase (AchE) as well as the concentration of vitellogenin (Vg) in the liver were measured. Results show that activities of MO, GST and AchE, and Vg levels in normal frogs (male/female) were 0.09±0.02/0.09±0.01 DA min-1 mg-1 protein, 0.12±0.04/0.13±0.04DA min-1 mg-1 protein, 6.13±2.69/6.01±2.09 U mg-1 protein and 0.87±0.42/2.18±0.50 μg mg-1 protein, respectively. Activities of MO, GST and AchE, and Vg levels in malformed frogs (male/female) were 0.15±0.04/0.21±0.07DA min- 1 mg-1 protein, 0.27±0.08/0.30±0.12DA min-1 mg-1 protein, 4.59±2.71/5.19±3.74 U mg-1 protein and 1.46±0.61/ 3.15±0.88μg mg-1 protein, respectively in KP site, and were 0.16±0.69/0.18±0.07DA min-1 mg-1 protein, 0.21±0.07/0.24±0.08DA min-1 mg-1 protein, 5.13±4.58/3.94±1.33 U mg-1 protein and 2.23±1.47/4.11±1.63 μg mg-1 protein, respectively in T site. These results indicate that male and female malformed frogs in both rivers upstream are found with higher activities. No significant difference in AchE activity was found between normal and malformed frogs in this investigation. It is therefore reasonable to speculate that the organic chemicals released from agricultural activities are presumable the main factors that lead to the malformation of frogs.