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.
J Endocrinol
; 112(2): 323-32, 1987 Feb.
Article
em En
| MEDLINE
| ID: mdl-3819643
ABSTRACT
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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Base de dados:
MEDLINE
Assunto principal:
Reprodução
/
Esteroides
/
Testículo
/
Peixes-Gato
Limite:
Animals
Idioma:
En
Ano de publicação:
1987
Tipo de documento:
Article