Regression analysis was performed between the kinetic parameters for the

glucuronidation of OH-PCBs and several physical parameters for these substrates (Table

4-5). The data for 40HBP was not used since this compound is not a OH-PCB. The

affinity of intestinal UGTs was negatively correlated with the Connolly solvent-

accessible surface area, the molecular surface area, solvent-excluded volume, ovality,

dihedral angle, log P, and positively correlated with pKa. The maximum rate of hepatic

glucuronidation was negatively correlated with the Connolly solvent-accessible surface

area, the molecular surface area, solvent-excluded volume, ovality, and log P, and

positively correlated with pKa (which showed a similar relationship with intestinal Vmax).

Ovality was also significantly negatively correlated with the maximum rate of intestinal

glucuronidation of the OH-PCBs studied (Figure 4-5).

 A paired t-test performed in order to investigate the physicochemical parameters

involved in the significant decrease in Vmax observed for the glucuronidation of OH-

PCBs with two chlorine atoms flanking the phenolic group revealed that, for OH-PCBs

with this structural arrangement, pKa was decreased (p=0.02), while log P, and

parameters indicating molecular size (CAA, CMA, CSEV, ovality) were all increased (all

p <0.0001).