Androgen-dependence of ornithine decarboxylase in the rat epididymis

Heras, M. A. De Las; Calandra, Ricardo S.

doi:10.1530/jrf.0.0790009

Cited by 15 publications

(11 citation statements)

References 17 publications

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“…Our results show that castration rapidly results in a decrease in the amount of putrescine without changes in the amounts of spermidine or spermine. Taking into account the observation that ODC activity cannot be detected 24 h after castration (de las Heras & Calandra, 1987), and that the decrease in putrescine content is prevented by testosterone, we suggest that at least an important fraction of the putrescine measured in the epididymis is synthesized within the epididymis. The fact that 48 h after castration the amounts of spermidine and spermine in the epididymis have not been affected suggests a lower turnover of these compounds with respect to their precursor.…”

Section: Discussionmentioning

confidence: 80%

“…In contrast, no attention has been paid to the contribution of polyamines to the process of sperm maturation in the epididymis. We have detected ODC activity in rat epididymis and demon¬ strated that this enzyme is strictly androgen dependent (de las Heras & Calandra, 1987;de las Heras et al, 1988). We have also observed epididymal SAMDC activity, necessary for the synthesis of spermidine and spermine; and its androgenic control (de las Heras & Calandra, 1991 (Merck,250 µ thickness), previously activated at 110°C for 1 h. Standards containing 10 nmol of putrescine, spermidine and spermine were treated in the same way as the sample, and volumes containing 0-25, 0-5, 1 0 and 20 nmol were spotted on the same plates.…”

Section: Introductionmentioning

confidence: 88%

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Androgenic control of polyamine concentrations in rat epididymis

Heras

Gonzalez²,

Calandra³

1992

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Summary. Unilateral orchidectomy resulted in a significant decrease in tissue content of putrescine and polyamines. However, no differences were detected when the results were expressed in terms of ng g \ m=-\ 1 tissue. At 48 h after bilateral orchidectomy, a significant decrease in putrescine content was observed, but spermidine and spermine content were unaffected. The observed decrease in putrescine was prevented by treatment with testosterone propionate, but neither spermidine nor spermine were affected. Bilateral orchidectomy resulted in a significant decrease in the tissue content of putrescine, spermidine and spermine after 7 days. Treatment with testosterone propionate increased the content of putrescine, spermidine and spermine in the epididymis by about 200%, 92% and 34%, respectively. When results were expressed as nmol g\ m=-\ 1, a significant decrease after castration in putrescine and spermidine, but not in spermine, was observed. Treatment with testosterone propionate restored putrescine concentration, but had no effect on spermidine and spermine concentrations. In castrated rats treated with testosterone propionate, the anti-androgen flutamide abolished the effect of the androgen on putrescine and spermidine content, but there was no effect on spermine.Acetylputrescine was not detected in the epididymis, while acetylpolyamines were detected at much lower concentrations than polyamines. After bilateral orchidectomy there was a decrease in the tissue content of all acetylpolyamines and an increase in their tissue concentration. The effect of castration on acetylpolyamine content was reversed by testosterone propionate treatment. We conclude that an active synthesis of polyamines occurs in the rat epididymis, and that this process depends upon the androgen environment. Regulation of ornithine decarboxylase activity appears to be the main step that is controlled by androgens.

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Section: Discussionmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 88%

Androgenic control of polyamine concentrations in rat epididymis

Heras

Gonzalez²,

Calandra³

1992

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“…L-[ l-14C]Omithine (sp act: 49-56 mCi/mmol), [ 1 ,2-3H]5a-androstan-3a, 17p-diol (sp act: 25.4 Ci/mmol), [ 1 ,2-3H]5a-dihydrotestosterone (sp act: 50.6 Cilmmol), and Omnifluor were purchased from New England Nuclear (Boston, MA, USA). [14C]Ornithine was purified as previously described [7]. Flutamide (cr-a-a-trifluoro-2-methyl-4'-nitro-m-propionotoluidine) and casodex (ICI 176,334: (2RS)-4-cyano-3(-4-fluorophenylsulfonyl)-2-anilide) were kindly supplied by Schering Canada (Quebec, Canada) and ICI Pharmaceuticals (Macclesfield, UK), through the courtesy of F. Labrie and B. Furr, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…ODC activity was measured in 20,OOOg supernatants from whole epididymides as previously described [7]. The enzymic activity was expressed in terms of pmol 14C0, releasedmg protein h-' or nmoVepididymis.…”

Section: Animals and Treatmentsmentioning

confidence: 99%

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Ornithine Decarboxylase Activity and Polyamine Levels in the Epididymis of Prepubertal Rat After Antiandrogen Administration

Rulli¹,

González-Calvar²,

Calandra³

1997

Archives of Andrology

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S‐Adenosyl‐L‐Methionine Decarboxylase Activity in the Rat Epididymis: Ontogeny and Androgenic Control

HERAS,

CALANDRA

1991

Journal of Andrology

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The authors describe the occurrence of high levels of S‐adenosyl‐L‐methionine decarboxylase (SAMDC) activity in the rat epididymis, and its ontogeny and androgenic control. As early as 15 days of age, SAMDC activity exists, although a peak of activity is observed at 25 days. Bilateral orchidectomy resulted in a decline of epididymal SAMDC activity. However, an androgen‐independent fraction, accounting for 34% of total activity, appears to exist in the epididymis. In 45‐day‐old orchidectomized rats, SAMDC activity was stimulated by testosterone treatment in a dose‐dependent manner. However, treatment of 45‐day‐old intact animals with a high dose of the androgen failed to modify SAMDC activity, indicating that, at this age, the enzyme is maximally stimulated by endogenous androgens. The observed effect of testosterone on castrated rats was completely abolished by concomitant treatment with the antiandrogen flutamide. This compound was ineffective on the androgen‐insensitive fraction. To assess the contribution of circulating and luminal androgens to the maintenance of epididymal SAMDC, rats were unilaterally orchidectomized and activity was determined in both epididymides after 7 days. The SAMDC activity was identical in epididymides from both sides, suggesting that circulating androgens suffice to maintain normal levels of activity. It was concluded that androgens regulate epididymal SAMDC activity, although an androgen‐independent fraction appears to exist.

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Androgen-dependence of ornithine decarboxylase in the rat epididymis

Cited by 15 publications

References 17 publications

Androgenic control of polyamine concentrations in rat epididymis

Androgenic control of polyamine concentrations in rat epididymis

Ornithine Decarboxylase Activity and Polyamine Levels in the Epididymis of Prepubertal Rat After Antiandrogen Administration

S‐Adenosyl‐L‐Methionine Decarboxylase Activity in the Rat Epididymis: Ontogeny and Androgenic Control

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