The effects of aromatizable androgens, non-aromatizable androgens, and estrogens on gonadotropin release in castrated African catfish, Clarias gariepinus (Burchell)

Leeuw, R. de; Wurth, Y.A.; Zandbergen, Matthijs A.; Peute, J.; Goos, H.J.Th.

doi:10.1007/bf00218066

Cited by 55 publications

(33 citation statements)

References 25 publications

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“…Contrary to the results observed in cells from sexually immature rainbow trout, treatment of pituitary cells from spawning rainbow trout with E2 did not affect LH-β transcript levels (Xiong et al, 1994), and in mature rainbow trout, injection with E2 was found to reduce circulating LH levels (Billard et al, 1977). In African catfish, treatment with an aromatizable androgen was found to reduce GtH release, while it stimulated LH synthesis (De Leeuw et al, 1986). In general, pituitary cells from teleosts have stronger aromatase activity than those from mammals (Callard et al, 1990(Callard et al, , 1993.…”

Section: The Role Of Gonadal Hormones In the Control Of Pituitary Goncontrasting

confidence: 82%

Hormonal regulation of follicular atresia in teleost fish

Habibi

Andreu-Vieyra

2007

The Fish Oocyte

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Section: The Role Of Gonadal Hormones In the Control Of Pituitary Goncontrasting

confidence: 82%

Hormonal regulation of follicular atresia in teleost fish

Habibi

Andreu-Vieyra

2007

The Fish Oocyte

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“…This conversion is particularily high in teleosts (Callard, 1982). Aromatization has been indicated as being of importance for androgen effects on the,,GTH cells in the young rainbow trout, Salmo gairdneri (Crim et al, 1981) and in the adult African catfish, Clarias gariepinus (de Leeuw et al, 1986). The object of the present study was to investigate this component in the neuroendocrine system in mature and immature Atlantic salmon Parr.…”

mentioning

confidence: 95%

Aromatase activity in brain and pituitary of immature and mature atlantic salmon (Salmo salar L.) parr

Andersson

Borg

Lambert

1988

General and Comparative Endocrinology

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Brain homogenates from Atlantic salmon parr converted tritiated androstenedione to testosterone, estrone, and 17P-estradiol. The formation of estrogens was markedly higher in homogenates of whole brains from mature parr males than from immature pan: males. The highest estrogen synthesis was found in the telencephalon and diencephalon. In both of these parts the estrogen production was higher in mature males than in immature males. There was no difference in estrogen formation by pituitaries from immature female and immature male Parr, whereas the formation of estrogens and testosterone was higher in the mature male Parr. Q

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“…The presence of these steroids was also demonstrated in the blood (De Leeuw et al, 1986). Hay et al (1976) have suggested that the glucuronides found in the rainbow trout skin could be detoxification products.…”

Section: Discussionmentioning

confidence: 95%

The skin of the male African catfish, Clarias gariepinus: A source of steroid glucuronides

Ali¹,

Schoonen²,

Lambert³

et al. 1987

General and Comparative Endocrinology

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Steroid metabolism in the skin of mature male African cattish, Clarias gariepinus, reared in the laboratory, was studied in vitro by tissue incubations with [3H] was transformed mainly to 5-androstene-3P,17@-diol. The products of 17a-hydroxyprogesterone incubations were Sp-pregnane-3a,17a-diol-20-one, SP-pregnane-3a,l7u, 20p-triol, and SP-pregnan-17a-ol-3,20-dione. The major steroids of androstenedione incubations were etiocholanolone, testosterone, and androsterone. Testosterone was converted mainly to etiocholanolone and androstenedione, and only small quantities of 11 P-hydroxytestosterone, 1 l-ketotestosterone, and 1 I-ketoandrostenedione were the metabolites found in 1 l@hydroxyandrostene-dione incubation. These results demonstrated the presence of the enzymes 5a-and 5@re-ductases and 3a-, lll3-, 17p-, and 20P-hydroxysteroid dehydrogenases in the skin. From enzymehistochemical results it appeared that the steroid conversions take place in the epithelial cells. Moreover, the presence of UDP-glucose dehydrogenase, an enzyme involved in the synthesis of glucuronic acid, in these cells indicates the possibility of steroid glucuronide formation. Indeed significant amounts of water-soluble steroid conjugates, particularly SP-dihydrotestosteroneand testosterone-glucuronide, were found in the incubations with androstenedione and testosterone, indicating the presence of the UDP-glucuronosyl transferase in the cattish skin. In the light of these results, a role of the skin of African catfish in the production of semiochemicals having pheromonal properties is discussed. 0 1987 Academic Press, Inc.

show abstract

The effects of aromatizable androgens, non-aromatizable androgens, and estrogens on gonadotropin release in castrated African catfish, Clarias gariepinus (Burchell)

Cited by 55 publications

References 25 publications

Hormonal regulation of follicular atresia in teleost fish

Hormonal regulation of follicular atresia in teleost fish

Aromatase activity in brain and pituitary of immature and mature atlantic salmon (Salmo salar L.) parr

The skin of the male African catfish, Clarias gariepinus: A source of steroid glucuronides

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