Effects of different steroid-biosynthesis inhibitors on the testicular steroidogenesis of the toad Bufo arenarum

Testis fragments from Bufo arenarum were incubated with [7(n)-3H]pregnenolone (P5), [1,2-3H]de-hydroepiandrosterone (DHEA) and [1,2,6,7-3H]testosterone (T), and different steroid-biosynthesis inhibitors. The inhibitors used were: cyanoketone (CNK), spironolactone (SPNL) and finasteride (FIN). CNK si...

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Detalles Bibliográficos
Autores principales: Canosa, Luis Fabián, Ceballos, Nora Raquel
Publicado: 2001
Materias:
Amphibia
Anura
Enzyme-inhibition
Steroid-hormones
Testes
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01741578_v171_n6_p519_Canosa
http://hdl.handle.net/20.500.12110/paper_01741578_v171_n6_p519_Canosa
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_01741578_v171_n6_p519_Canosa
record_format dspace
spelling paper:paper_01741578_v171_n6_p519_Canosa2023-06-08T15:18:54Z Effects of different steroid-biosynthesis inhibitors on the testicular steroidogenesis of the toad Bufo arenarum Canosa, Luis Fabián Ceballos, Nora Raquel Amphibia Anura Enzyme-inhibition Steroid-hormones Testes Testis fragments from Bufo arenarum were incubated with [7(n)-3H]pregnenolone (P5), [1,2-3H]de-hydroepiandrosterone (DHEA) and [1,2,6,7-3H]testosterone (T), and different steroid-biosynthesis inhibitors. The inhibitors used were: cyanoketone (CNK), spironolactone (SPNL) and finasteride (FIN). CNK significantly increased the recovery of 3β-hydroxy-5-ene steroids while SPNL reduced the metabolism of P5 and the production of C19-steroids. The metabolism of C19-substrates was only modified by CNK, which reduced the transformation of DHEA without modifying the metabolism of T. To determine the degree of inhibition exerted by the inhibitors used, the activities of the enzymes were estimated as the percentage of their contribution to the total steroid metabolism. CNK strongly inhibited the activity of hydroxysteroid dehydrogenase/isomerase if its contribution was estimated using both P5 and DHEA. If the analysis was made considering both activities associated to cytochrome P450 17α-hydroxylase, C17-20 lyase (P450c17), it became evident that SPNL inhibited both of them. The percent contribution of 17β-hydroxysteroid dehydrogenase (17βHSD) activity diminished in the presence of CNK only if it was estimated considering P5 and DHEA metabolism. SPNL produced a significant inhibition of 17βHSD when its contribution was estimated considering P5 metabolism. However, SPNL was insufficient if DHEA or T were considered. The effect of SPNL on the contribution of 17βHSD could be due to the reduction of C19-substrates. The activity of 5α-reductase was inhibited by CNK only if results from P5 and DHEA were considered. Fil:Canosa, L.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Ceballos, N.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2001 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01741578_v171_n6_p519_Canosa http://hdl.handle.net/20.500.12110/paper_01741578_v171_n6_p519_Canosa
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Amphibia
Anura
Enzyme-inhibition
Steroid-hormones
Testes
spellingShingle Amphibia
Anura
Enzyme-inhibition
Steroid-hormones
Testes
Canosa, Luis Fabián
Ceballos, Nora Raquel
Effects of different steroid-biosynthesis inhibitors on the testicular steroidogenesis of the toad Bufo arenarum
topic_facet Amphibia
Anura
Enzyme-inhibition
Steroid-hormones
Testes
description Testis fragments from Bufo arenarum were incubated with [7(n)-3H]pregnenolone (P5), [1,2-3H]de-hydroepiandrosterone (DHEA) and [1,2,6,7-3H]testosterone (T), and different steroid-biosynthesis inhibitors. The inhibitors used were: cyanoketone (CNK), spironolactone (SPNL) and finasteride (FIN). CNK significantly increased the recovery of 3β-hydroxy-5-ene steroids while SPNL reduced the metabolism of P5 and the production of C19-steroids. The metabolism of C19-substrates was only modified by CNK, which reduced the transformation of DHEA without modifying the metabolism of T. To determine the degree of inhibition exerted by the inhibitors used, the activities of the enzymes were estimated as the percentage of their contribution to the total steroid metabolism. CNK strongly inhibited the activity of hydroxysteroid dehydrogenase/isomerase if its contribution was estimated using both P5 and DHEA. If the analysis was made considering both activities associated to cytochrome P450 17α-hydroxylase, C17-20 lyase (P450c17), it became evident that SPNL inhibited both of them. The percent contribution of 17β-hydroxysteroid dehydrogenase (17βHSD) activity diminished in the presence of CNK only if it was estimated considering P5 and DHEA metabolism. SPNL produced a significant inhibition of 17βHSD when its contribution was estimated considering P5 metabolism. However, SPNL was insufficient if DHEA or T were considered. The effect of SPNL on the contribution of 17βHSD could be due to the reduction of C19-substrates. The activity of 5α-reductase was inhibited by CNK only if results from P5 and DHEA were considered.
author Canosa, Luis Fabián
Ceballos, Nora Raquel
author_facet Canosa, Luis Fabián
Ceballos, Nora Raquel
author_sort Canosa, Luis Fabián
title Effects of different steroid-biosynthesis inhibitors on the testicular steroidogenesis of the toad Bufo arenarum
title_short Effects of different steroid-biosynthesis inhibitors on the testicular steroidogenesis of the toad Bufo arenarum
title_full Effects of different steroid-biosynthesis inhibitors on the testicular steroidogenesis of the toad Bufo arenarum
title_fullStr Effects of different steroid-biosynthesis inhibitors on the testicular steroidogenesis of the toad Bufo arenarum
title_full_unstemmed Effects of different steroid-biosynthesis inhibitors on the testicular steroidogenesis of the toad Bufo arenarum
title_sort effects of different steroid-biosynthesis inhibitors on the testicular steroidogenesis of the toad bufo arenarum
publishDate 2001
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01741578_v171_n6_p519_Canosa
http://hdl.handle.net/20.500.12110/paper_01741578_v171_n6_p519_Canosa
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AT ceballosnoraraquel effectsofdifferentsteroidbiosynthesisinhibitorsonthetesticularsteroidogenesisofthetoadbufoarenarum
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