Typescript (photocopy) / v, 179, viii leaves, [3] leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Biochemistry, 1983

Thesis (Ph. D.)--Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, 1983. / Includes bibliographical references (p. 252-270).

Thesis (M. Med. Sc.)--University of Hong Kong, 2007.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Biochemistry, 1983. / Typescript (photocopy).

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [162]-177).

Thesis (Ph. D.)--Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, 1983. / Includes bibliographical references (p. 252-270).

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this study is to determine if propoxyphene and norpropoxyphene are mechanism-based (irreversible) inhibitors of CYP3A, and to determine if propoxyphene and norpropoxyphene are reversible inhibitors of CYP3A. Mechanismbased inhibition is a type of irreversible inhibition that results from an inhibitor or its metabolite binding to an enzyme during drug metabolism, which renders the enzyme nonfunctional. Propoxyphene is an analgesic that is frequently prescribed in the United States and Europe. It is metabolized by CYP3A enzymes, and is an irreversible inhibitor of CYP3A4. The major metabolite of propoxyphene is norpropoxyphene, which has not been extensively studied for enzyme inhibition. Proadifen (SKF-525a) is not a marketed drug, but it is a known CYP inhibitor that is structurally similar to propoxyphene and norpropoxyphene. Propoxyphene, norpropoxyphene, and proadifen were characterized in these studies with CYP3A4(+b5), CYP3A5(+b5) and pooled human liver microsomes. Time-dependent and concentration-dependent loss of activity of CYP3A was measured by formation of testosterone product. Propoxyphene and norpropoxyphene exhibited the greatest inhibition with CYP3A in human liver microsomes, followed by CYP3A4(+b5), and CYP3A5(+b5). Both compounds formed metabolic-inhibitor complexes with vi CYP3A4(+b5) and CYP3A5(+b5), but not with human liver microsomes. Proadifen was a more potent inhibitor of CYP3A4(+b5) than of human liver microsomes and CYP3A5(+b5). The KI values of propoxyphene and CYP3A4(+b5) and human liver microsomes fall within the range of reported therapeutic blood levels of propoxyphene, with reversible inhibition constants (Ki values) above therapeutic blood concentrations for propoxyphene and norpropoxyphene. The KI values of norpropoxyphene and CYP3A4(+b5) and human liver microsomes are higher than most reported blood levels, except for blood levels after repeated dosing of propoxyphene at high concentrations. The predicted change in the area under the plasma concentration versus time curve of an orally administered CYP3A substrate with propoxyphene (AUC'po/AUCpo) was calculated for common CYP3A substrates. The AUC'po/AUCpo ratios are four to twenty-five times higher with co-administration of propoxyphene based on in vitro kinetic parameters. Propoxyphene and norpropoxyphene may cause adverse events when chronically administered at high doses and/or when co-administered with other CYP3A substrates.

Detoxification of compounds occurs in two phases. In phase I, a functional group on the toxicant is made available for subsequent Phase II reactions. In phase II, the functional groups are conjugated to a compound that will increase the solubility of the toxicant, enhancing its elimination. Uridine diphosphate glucuronyl transferase (UDPGT) is one microsomal enzyme involved in phase II reactions. It catalyzes the conjugation of toxic compounds with glucuronic acid in reactions in which uridine diphosphate glucuronic acid (UDPGA) is the donor substrate. A new purification procedure for UDPGT has been developed. This procedure includes a Polyethylene glycol fractionation, ion exchange chromatography with DEAE Bio-gel A and affinity chromatography with UDP-hexanolamine-Sepharose. The purification was monitored for three different substrates, bilirubin, 4-nitrophenol (PNP) and 7-hydroxy-4-methylcoumarin (HMC). For this last substrate, HMC, a new continuous fluorometric assay was developed. The purification fold and activity recovery, respectively, towards each substrate was as follows: bilirubin, 31 and 80%; PNP, 31 and 80%; and HMC, 24 and 60%. The significance of these results is discussed with reference to the activation of UDPGT in microsomes by detergents and the reactivation of purified UDPGT by phospholipids. / M.S.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 6 uppsatser.