Abstract of Dissertation Presented to the Graduate School
 of the University of Florida in Partial Fulfillment of the
 Requirements for the Degree of Doctor of Philosophy

 PHASE II BIOTRANSFORMATION OF XENOBIOTICS BY POLAR BEAR (Grsus
 maritimus) AND CHANNEL CATFISH (Ictalurus punctatus)

 By

 James C. Sacco

 August 2006

Chair: Margaret O. James
Major Department: Medicinal Chemistry

 Both polar bears and channel catfish are subject to bioaccumulation of persistent

toxic environmental pollutants including hydroxylated compounds, which are potential

substrates for detoxification via phase II conjugative processes such as sulfonation and

glucuronidation. The objectives of this dissertation were to (a) study the capability of

polar bear liver to sulfonate a structurally diverse group of environmental chemicals, and

to study the glucuronidation of 3-OH-B[a]P; (b) study the effects of chlorine substitution

pattern on the glucuronidation of polychlorinated biphenylols (OH-PCBs) by catfish liver

and proxi mal inte sti ne; (c) clone UDP -glucurono syltran sferase (UGT) from catfish liver

and intestine; (d) develop a method to determine physiological concentrations of UDP-

glucuronic acid (UDPGA) in catfish liver and intestine.

 In the polar bear, the efficiency of sulfonation decreased in the order 3-OH-

B[a]P>>>triclosan>>4'-OH-PCB79>OHMXC>4'-OH-C165>TCPM>4'-OH-PCB 159

>PCP, all of which produced detectable sulfate conjugates. Substrate inhibition was