Ornithine decarboxylase activity as a marker of androgen and antiandrogen action in the rat epididymis

After castration, there was a marked decrease in serum androgen concentration at 6 h, and a dramatic inhibition of ornithine decarboxylase (ODC) at 12 h. Administration of testosterone propionate to castrated rats at a dose of 0.05 mg/animal restored ODC activity to the normal value. However, no cha...

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Autores principales: De Las Heras, M.A., Suescun, M.O., Calandra, R.S.
Formato: JOUR
Materias:
androgen
flutamide
ornithine decarboxylase
testosterone propionate
animal experiment
castration
epididymis
male
nonhuman
rat
Animalia
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00224251_v83_n1_p177_DeLasHeras
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00224251_v83_n1_p177_DeLasHeras
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spelling todo:paper_00224251_v83_n1_p177_DeLasHeras2023-10-03T14:32:54Z Ornithine decarboxylase activity as a marker of androgen and antiandrogen action in the rat epididymis De Las Heras, M.A. Suescun, M.O. Calandra, R.S. androgen flutamide ornithine decarboxylase testosterone propionate animal experiment castration epididymis male nonhuman rat Animalia After castration, there was a marked decrease in serum androgen concentration at 6 h, and a dramatic inhibition of ornithine decarboxylase (ODC) at 12 h. Administration of testosterone propionate to castrated rats at a dose of 0.05 mg/animal restored ODC activity to the normal value. However, no change was observed when intact rats were treated with testosterone even at a 40-fold higher dose, indicating that endogenous androgens present in intact rats are far in excess for maintenance of maximal levels of activity. Administration of the antiandrogen flutamide to intact rats caused a moderate decrease in epididymal weight, whereas this effect was more pronounced in castrated, androgen-treated rats. In the latter, the effect of flutamide was significant at the lowest dose used (0.5 mg/day). ODC activity was significantly decreased by flutamide treatment of intact rats, but even at the highest dose used (10 mg/day) only a 39% inhibition was observed. In flutamide-treated rats, LH concentrations were markedly increased, as were serum and epididymal androgens. In androgen-treated castrated rats, flutamide caused epididymal ODC to fall to undetectable values. These results show that: (1) androgens are essential for the maintenance of ODC activity in the epididymis; (2) epididymal ODC activity is maximally stimulated by endogenous androgens, at least in the pubertal rat; (3) the apparent potency of flutamide is substantially lowered by an increase in epididymal androgens. We suggest that ODC is a sensitive marker of the action of androgens and antiandrogens in the epididymis. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00224251_v83_n1_p177_DeLasHeras
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic androgen
flutamide
ornithine decarboxylase
testosterone propionate
animal experiment
castration
epididymis
male
nonhuman
rat
Animalia
spellingShingle androgen
flutamide
ornithine decarboxylase
testosterone propionate
animal experiment
castration
epididymis
male
nonhuman
rat
Animalia
De Las Heras, M.A.
Suescun, M.O.
Calandra, R.S.
Ornithine decarboxylase activity as a marker of androgen and antiandrogen action in the rat epididymis
topic_facet androgen
flutamide
ornithine decarboxylase
testosterone propionate
animal experiment
castration
epididymis
male
nonhuman
rat
Animalia
description After castration, there was a marked decrease in serum androgen concentration at 6 h, and a dramatic inhibition of ornithine decarboxylase (ODC) at 12 h. Administration of testosterone propionate to castrated rats at a dose of 0.05 mg/animal restored ODC activity to the normal value. However, no change was observed when intact rats were treated with testosterone even at a 40-fold higher dose, indicating that endogenous androgens present in intact rats are far in excess for maintenance of maximal levels of activity. Administration of the antiandrogen flutamide to intact rats caused a moderate decrease in epididymal weight, whereas this effect was more pronounced in castrated, androgen-treated rats. In the latter, the effect of flutamide was significant at the lowest dose used (0.5 mg/day). ODC activity was significantly decreased by flutamide treatment of intact rats, but even at the highest dose used (10 mg/day) only a 39% inhibition was observed. In flutamide-treated rats, LH concentrations were markedly increased, as were serum and epididymal androgens. In androgen-treated castrated rats, flutamide caused epididymal ODC to fall to undetectable values. These results show that: (1) androgens are essential for the maintenance of ODC activity in the epididymis; (2) epididymal ODC activity is maximally stimulated by endogenous androgens, at least in the pubertal rat; (3) the apparent potency of flutamide is substantially lowered by an increase in epididymal androgens. We suggest that ODC is a sensitive marker of the action of androgens and antiandrogens in the epididymis.
format JOUR
author De Las Heras, M.A.
Suescun, M.O.
Calandra, R.S.
author_facet De Las Heras, M.A.
Suescun, M.O.
Calandra, R.S.
author_sort De Las Heras, M.A.
title Ornithine decarboxylase activity as a marker of androgen and antiandrogen action in the rat epididymis
title_short Ornithine decarboxylase activity as a marker of androgen and antiandrogen action in the rat epididymis
title_full Ornithine decarboxylase activity as a marker of androgen and antiandrogen action in the rat epididymis
title_fullStr Ornithine decarboxylase activity as a marker of androgen and antiandrogen action in the rat epididymis
title_full_unstemmed Ornithine decarboxylase activity as a marker of androgen and antiandrogen action in the rat epididymis
title_sort ornithine decarboxylase activity as a marker of androgen and antiandrogen action in the rat epididymis
url http://hdl.handle.net/20.500.12110/paper_00224251_v83_n1_p177_DeLasHeras
work_keys_str_mv AT delasherasma ornithinedecarboxylaseactivityasamarkerofandrogenandantiandrogenactionintheratepididymis
AT suescunmo ornithinedecarboxylaseactivityasamarkerofandrogenandantiandrogenactionintheratepididymis
AT calandrars ornithinedecarboxylaseactivityasamarkerofandrogenandantiandrogenactionintheratepididymis
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