Hypothesis ................ ...............62... Method ology (part 1) ............... ...............62... Results and discussion (part 1) .............. ...............74.... Methodology (part 2) .........__.. ..... ._ __ ...............79.... Overview of RLM-RACE ....._.. ................ ........_._ ......... 7 5' RLM-RACE procedure .............. ...............8 4.... 3' RACE procedure ..................... ...............86. PCR amplification of entire UGT gene ......___ ..... .._.. ......_._.........8 Results (part 2)............... ... ...............8 Nucleotide sequence analysis ................ ...............89........... .... Protein sequence analysis ................ ...............100................ Cloning of entire UGT gene ................. ...............104........... ... Discussion ................. ...............107................ Limitations ................. ............ ...............110...... Conclusions and recommendations ................. ......... ......... .............1 6 DETERMINATION OF PHYSIOLOGICAL UDPGA CONCENTRATIONS IN CHANNEL CATFISH LIVER AND INTESTINE ......____ ........ __ ..............116 UDP-Glucuronic Acid (UDPGA) ................. ...............116................ Obj ective ................. ....._ __ ...............118...... M ethod Development ................. ...............118....... ...... Sample Digestion ....__ ................. .........__..........19 H PLC ............ _...... ...............1 1.... Final M ethod .............. ...............123.... Re sults............ ..... .. ...............125... Discussion ............ __... ...._ ..... ._ ............12 Conclusions and Recommendations ....__ ......_____ .......___ .............2 APPENDIX A SEQUENCES OF UGT PARTIAL CLONES AND AMPLICONS ................... .....131 B SEQUENCES FOR UGT FULL-LENGTH CLONES FROM CATFISH LIVER..138 LIST OF REFERENCES ........._._ ...... ..... ...............144.... BIOGRAPHICAL SKETCH ........._... ...... .___ ...............157....