Age-dependent changes in the multiple forms of the soluble 17 beta-hydroxysteroid dehydrogenase of female rabbit liver.
The soluble NADP-dependent 17 beta-hydroxysteroid dehydrogenase activity of female rabbit liver increases with the age of the animal, the specific activity of the enzyme in the 56-day-old rabbit being 3 times that of the 28-day-old animal. The increase in activity is accompanied by a change in the molecular heterogeneity of the enzyme. Three forms (enzymes I, II and III) were identified in the liver cytosol of the 56-day-old female rabbit, whereas only one major form (enzyme IIIY) was present in the 28-day-old animal. Peptide maps of the four purified enzymes showed that there were minor differences in structure. The enzyme present in the liver of the 28-day-old rabbit was distinct from the three enzymes of the 56-day-old animal. All of the enzymes exhibited bifunctional activity, having 17 beta-hydroxysteroid dehydrogenase activity towards androgen and oestrogen substrates and 3 alpha-hydroxysteroid dehydrogenase activity towards androgens of the 5 beta-androstane series. The differences in substrate specificity of the enzymes paralleled their differences in structure. The data suggest that one enzyme (enzyme III) may have a special role in steroid metabolism during development in the female rabbit.
Antoun
G R
GR
Williamson
D G
DG
D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000375:Aging; D000818:Animals; D002846:Chromatography, Affinity; D003600:Cytosol / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007527:Isoenzymes / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D009249:NADP / Q000494:pharmacology; D010446:Peptide Fragments / Q000032:analysis; D011817:Rabbits; D013379:Substrate Specificity
D007527:Isoenzymes; D010446:Peptide Fragments; D009249:NADP; D015067:17-Hydroxysteroid Dehydrogenases; C032690:3-alpha-(17-beta)-hydroxysteroid dehydrogenase (NAD(+))