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Memorial University - Electronic Theses and Dissertations 2
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Title3a-Hydroxysteroid dehydrogenase activity in the cytosolic fractions of human placenta, kidney and liver
AuthorGyapong, Tony Emmanuel
DescriptionThesis (M.Sc.)--Memorial University of Newfoundland, 1987. Medicine
Paginationxii, 156 leaves : ill.
Subject.MESH3-Hydroxysteriid Dehydrogenases; Cytosol; Placenta--enzymology; Kidney--enzymology; Liver--enzymology
Degree GrantorMemorial University of Newfoundland. Faculty of Medicine
NotesBibliography: leaves 132-156.
AbstractAlthough the major metabolites of 3-ketosteroids voided in human urine are 3α-hydroxysteroids or their derivatives, there has been very little published work on the purification and characterization of the human 3α-hydroxysteroid dehydrogenases which must be involved in their genesis. -- The presence of the 3α-hydroxysteroid dehydrogenases in human liver, kidney and placenta has been demonstated by incubation of extracts of these tissues with 17α-methyl-5α-androstane-3α, 17β-diol which was converted to the 3-ketone. This was identified by thin layer chromatography and by high performance liquid chromatography and by further characterization after sodium borohydride reduction of the 3-ketone to the 3β-alcohol. -- The NAD-dependent liver cytosol enzyme activity found in the 40-60% ammonium sulphate precipitate has been partially purified using ion-exchange and gel filtration chromatography. The 3α-HSD activity appears to reside in a number of isozymes separable by carboxymethyl-cellulose chromatography one is tentatively identified as being a human liver ADH, β1β1 which was shown by iso-electric focussing to have a pI between 9 and 10. 4-Methyl pyrazole was found to inhibit the ethanol dehydrogenase activity but not the 3α-HSD activity of these isozymes. -- A two-fold ratio of 3α- : 3β-HSD activity was observed in the human kidney cytosol but the activity in the microsomal fraction was entirely due to 3β-HSD with only a trace of 3α-HSD activity. The 3α-HSD activity found in the cytosolic fraction of the human placenta was very unstable.
Resource TypeElectronic thesis or dissertation
FormatImage/jpeg; Application/pdf
SourcePaper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries
Local Identifier76083019
RightsThe author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
CollectionElectronic Theses and Dissertations
Scanning StatusCompleted
PDF File(18.30 MB) --
CONTENTdm file name99442.cpd