Seasonal changes in the activity of 11β-hydroxysteroid dehydrogenase in toad testes

In mammals, glucocorticoids (GC) are inactivated by the oxidative activity of 11β-hydroxysteroid dehydrogenase (11β-HSD). To study that mechanism in the testes of Bufo arenarum, 11β-HSD activity and plasma corticosterone (B) were determined in toads from pre- (PR), post- (P), and reproductive (R) pe...

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Detalles Bibliográficos
Autores principales: Denari, D., Ceballos, N.R.
Formato: SER
Materias:
11β-hydroxysteroid dehydrogenase
Corticosterone
Testis
Toad
11beta hydroxysteroid dehydrogenase
corticosterone
glucocorticoid
glucose 6 phosphatase
glycyrrhetinic acid
nicotinamide adenine dinucleotide
succinate dehydrogenase
animal experiment
animal tissue
cell nucleus
cellular distribution
conference paper
controlled study
corticosterone blood level
cytosol
enzyme activity
Leydig cell
male
Michaelis constant
microsome
mitochondrion
nonhuman
oxidation
reproduction
seasonal variation
testis
toad
Anura
Bufo arenarum
Mammalia
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00778923_v1040_n_p297_Denari
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:In mammals, glucocorticoids (GC) are inactivated by the oxidative activity of 11β-hydroxysteroid dehydrogenase (11β-HSD). To study that mechanism in the testes of Bufo arenarum, 11β-HSD activity and plasma corticosterone (B) were determined in toads from pre- (PR), post- (P), and reproductive (R) periods. Toad 11β-HSD is NAD+-dependent and strongly inhibited by glycyrrhetinic acid. Vmax is higher in the P period (1.37 vs. R: 0.13 and PR: 0.26 pmol/min-mg protein), whereas Km values (around 200 nM) remain constant. Plasma B concentrations (R: 178; PR: 61; P: 114 nM) are close to Km values, suggesting that, under baseline conditions, 11β-HSD could protect testes against GC action. © 2005 New York Academy of Sciences.

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