Effect of human chorionic gonadotropin and estradiol in vivo on estradiol binder and cytochrome P-450 concentrations in rat testis

Kühn‐Velten, N.; Staib, W.

doi:10.1016/0022-4731(84)90123-7

Cited by 7 publications

(1 citation statement)

References 34 publications

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“…5ß-A-dione, 5ß-androstane-3,l7-dione; A4, androstenedione; 5 --3 -1, androsterone; ETIO, aetiocholanolone; T, testosterone; 11 ß-4,11 ßhydroxyandrostenedione, llß-T, 11 ß-hydroxytestosterone; 11-KT, 11-ketotestosterone; T-GL, testosterone-glucoronide; 5ß-A-GL, 5ß-androstane-3a,17ß-diol-glucuronide. raga, Dufau & Catt, 1978;Chasalow, Marr, Haour & Saez, 1979;Nozu, Dehejia, Zawistowich et al 1982;Kühn-Velten & Staib, 1984). The reduction results from a reduced sensitivity of Leydig cells to hCG stimu¬ lation, because of a loss of gonadotrophin receptors (Bélanger, Cusan, Auclair et al 1980;Nozu, Dehejia, Zawistowich et al 1981Fishman, Rebois & Zaremba, 1985).…”

Section: Discussionmentioning

confidence: 99%

A quantitative study of steroid bioconversions in the testis of the African catfish, Clarias gariepinus (Burchell), under natural spawning and natural and cultivated non-spawning conditions

Schoonen¹,

Lambert²,

Resink³

et al. 1987

Journal of Endocrinology

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Quantitative aspects of bioconversions in the testes of the African catfish (Clarias gariepinus) were studied in vitro by incubation of tissue with [3H]pregnenolone or [3H]androstenedione. During the breeding period, spawning and non-spawning animals were collected from their natural habitat, the Hula nature reserve, in northern Israel. In the same period, non-spawning animals were collected from a fish pond in the same region. It was shown that spawning was accompanied by significant changes in steroid bioconversions, i.e. a reduction in androgen synthesis, especially of 11 beta-hydroxyandrostenedione and 11 beta-hydroxytestosterone and an increase in the production of C21-steroids, especially progesterone, 17 alpha-hydroxyprogesterone and a pregnenolone ester. These changes resulted from a decreased contribution of the cytochrome P-450 enzymes 17 alpha-hydroxylase, C17-20-lyase and 11 beta-hydroxylase. A rise in plasma gonadotrophin concentration was observed only in spawning catfish. In the absence of such an increase in plasma gonadotrophin, steroid synthesis in the testes of non-spawning feral and pond catfish was primarily directed towards the production of 11-oxygenated androgens and 5 beta-pregnane-3 alpha,17 alpha,20 alpha-triol. It is suggested that spawning is induced by gonadotrophin and the ensuing change in steroidogenesis. It is possible that husbandry conditions inhibit the necessary increase in gonadotrophin release.

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Section: Discussionmentioning

confidence: 99%

A quantitative study of steroid bioconversions in the testis of the African catfish, Clarias gariepinus (Burchell), under natural spawning and natural and cultivated non-spawning conditions

Schoonen¹,

Lambert²,

Resink³

et al. 1987

Journal of Endocrinology

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Cytochrome P450c17: Regulation of Gene Expression and Enzyme Function at the Bifurcation in Steroid Hormone Synthesis

Kühn‐Velten¹

1993

Cytochrome P450

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Differential down-regulation and induction responses of testicular steroidogenic cytochromes P-450(cscc) and P-450(C17α) to human choriogonadotropin

1986

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Evidence is presented that the regulation of the cytochrome P-450(C17 alpha) of the steroid-17 alpha-monooxygenase and of the cytochrome P-450(cscc) of the cholesterol-monooxygenase by human choriogonadotropin (hCG) in vivo is mediated by differential mechanisms in the adult rat testis. An initial down-regulation of the cytochrome P-450(C17 alpha) but not of the P-450(cscc) can be demonstrated. Furthermore, induction of the cytochrome P-450(cscc) requires exposure to higher hCG doses (32% of the maximal induction rate of 43.7 pmol/(testis x d) are achieved with 4IU hCG/single dose) than induction of the P-450(C17 alpha) (59% of the maximal induction rate of 48.4 pmol/(testis x d) with 4IU hCG/single dose). Finally, induction of cytochrome P-450(cscc) starts faster after initiation of hCG treatment than induction of P-450(C17 alpha).

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Effect of human chorionic gonadotropin and estradiol in vivo on estradiol binder and cytochrome P-450 concentrations in rat testis

Cited by 7 publications

References 34 publications

A quantitative study of steroid bioconversions in the testis of the African catfish, Clarias gariepinus (Burchell), under natural spawning and natural and cultivated non-spawning conditions

A quantitative study of steroid bioconversions in the testis of the African catfish, Clarias gariepinus (Burchell), under natural spawning and natural and cultivated non-spawning conditions

Cytochrome P450c17: Regulation of Gene Expression and Enzyme Function at the Bifurcation in Steroid Hormone Synthesis

Differential down-regulation and induction responses of testicular steroidogenic cytochromes P-450(cscc) and P-450(C17α) to human choriogonadotropin

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