Hormonal regulation of in vivo and in vitro oocyte maturation in the catfish, Heteropneustes fossilis (bloch)

Sundararaj, Bangalore I.; Goswami, Shashi V.

doi:10.1016/0016-6480(77)90079-x

Cited by 76 publications

(22 citation statements)

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“…The patterns of periovulatory changes in OE 2 and CE-related enzymes strongly indicate enhanced OE 2 catabolism towards CE formation and degradation in the catfish ovary. Since oestrogens have little or even an inhibitory role on oocyte final (meiotic) maturation in teleosts including the catfish (Sundararaj & Goswami 1977, Nagahama 1987, their removal by converting into CE may be an important physiological step during the periovulatory period. A direct demonstration of CEs and their metabolites remains.…”

Section: Discussionmentioning

confidence: 99%

“…The C. batrachus oocytes showed a higher response than the H. fossilis oocytes. The MIS property of the CEs seems to be associated with the hydroxylations at 2-or 4-position of the ring A, as their parent steroids exhibit only negligible MIS activity in catfish (Sundararaj & Goswami 1977, Upadhyaya & Haider 1986, Rao & Haider 1992). The structure-activity relationship needs to be examined in detail in future studies.…”

Section: Discussionmentioning

confidence: 99%

“…The strong inhibitory response of actinomycin D on CE-induced GVBD response is similar to that observed in gonadotrophininduced GVBD but different from other steroid-(e.g. deoxycorticosterone, 17 ,20 -DP) and insulin-like growth factor-I-induced oocyte maturation (Sundararaj & Goswami 1977, Goetz 1983, Nagahama 1987, Jalabert et al 1991. In the latter case, only translational activity (protein synthesis) was involved during the GVBD response.…”

Section: Discussionmentioning

confidence: 99%

“…Oocyte maturational and ovulatory events are initiated by the other gonadotrophin (gonadotrophin-II (GTH-II) or luteinizing hormone (LH)) through the mediation of a maturation-inducing hormone or substance (MIH or MIS), the most common being an ovarian progesterone derivative, 17 , as in many salmonids, cyprinids and silurids, or 17 ,20 ,20 , as in sciaenid fish (Goetz 1983, Nagahama 1987, Scott & Canario 1987, Thomas 1994. MIS activity was also demonstrated for corticosteroids (deoxycorticosterone and cortisol) in several teleosts including catfish (Goswami & Sundararaj 1974, Sundararaj & Goswami 1977, Goetz 1983, Upadhyaya & Haider 1986, Rao & Haider 1992, Haider 1997.…”

Section: Introductionmentioning

confidence: 94%

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Periovulatory changes in catfish ovarian oestradiol-17beta, oestrogen-2-hydroxylase and catechol-O-methyltransferase during GnRH analogue-induced ovulation and in vitro induction of oocyte maturation by catecholoestrogens

Senthilkumaran¹,

Joy²

2001

Journal of Endocrinology

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In the catfish Heteropneustes fossilis and Clarias batrachus, ovarian oestrogen-2-hydroxylase (OE-2-H) activity increased significantly at 8 h after the injection of an ovulatory dose (0·15 µg/g body weight) of a mammalian GnRH analogue ([-Ala 6 -Pro 9 ]-LHRH ethylamide) and was restored to the 0 h (control) level after egg-stripping at 16 h. On the other hand, ovarian oestradiol-17 (OE 2 ) level and catechol-O-methyltransferase (COMT) activity decreased significantly at 8 h. While the OE 2 level was restored to the 0 h level, COMT activity increased significantly at 16 h. Changes in ovarian OE 2 level and enzymes indicate higher synthesis of 2-hydroxylated catecholoestrogens and their degradation during the periovulatory period. Under in vitro conditions, the synthetic catecholoestrogens (CEs, 2-and 4-hydroxylated oestradiol-17 and oestrone (OE 1 )) induced germinal vesicle break down (GVBD) in a dose-(0·01-10 µg/ml) and duration-(1-36 h) dependent manner, the mean values of the responses being in the order 2-OH OE 2 >4-OH OE 2 > 2-OH OE 1 >4-OH OE 1 . The CE-induced GVBD response (8 h induction) was not blocked by prior and subsequent incubations with steroid synthesis inhibitors (cyanoketone, epostane and aminoglutethimide) up to 36 h, suggesting that de novo steroidogenesis is not essential for the response. The percentage of GVBD response to 2-h induction by CEs was significantly inhibited by actinomycin D (a transcriptional inhibitor) and cycloheximide (a translational inhibitor), indicating the involvement of both RNA and protein synthesis. The CE-induced 8-h stimulation of GVBD was mildly blocked by propranolol, the -adrenergic inhibitor, suggesting the response was partly mediated through a -adrenergic receptor mechanism. Incubations with phentolamine, an -adrenergic inhibitor, did not interfere with the CE-induced GVBD response. The results demonstrate CE-related enzymatic changes in teleost (catfish) ovaries and maturation-inducing substance activity of CEs.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

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Periovulatory changes in catfish ovarian oestradiol-17beta, oestrogen-2-hydroxylase and catechol-O-methyltransferase during GnRH analogue-induced ovulation and in vitro induction of oocyte maturation by catecholoestrogens

Senthilkumaran¹,

Joy²

2001

Journal of Endocrinology

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“…Ces effets sont au moins en partie médiés par des stéroïdes hormonaux, mais on manque de données précises sur la réponse des taux plasmatiques de ces composés à l'administration de GTH (cf. Fontaine, 1975 ;Billard et al, 1978 Goswami, 1977). …”

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Les hormones gonadotropes de l'hypophyse : biochimie et biologie comparées ; spécificité et évolution

Fontaine¹

1980

Reprod. Nutr. Dévelop.

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findings and demonstrated that, from fish to mammals, the antigenic determinants were better conserved for LH! than for the rx subunits. An hybrid molecule, formed by associating bovine LHa and c-GTHp, was more active in frogs than either of the mother-hormones, while it was inactive on adenylate cyclase in homogenates of rat or goldfish ovaries. This hybrid, however, was as active as c-GTH in increasing c-AMP concentration in pieces of eel ovary. Interestingly, sturgeon gonadotropin (aci-GTH) had somewhat similar biological properties. Aci-GTH subunits were partially purified, and an hybrid (bovine LHa-aci-GTH(3) was created. Both of the possible hybrids from the c-GTH and aci-GTH subunits could also be formed.The kinetics of subunit association have been studied in vitro. As compared with the formation of ovine LH, that of c-GTH was more rapid and less thermodependent. Thus, even though fish may live at low temperatures, GTH synthesis proceeds at a reasonable rate. The thermodependence of the formation of the hybrid, bovine LHa-c-GTHp, was identical to that of the c-GTH. Therefore, the subunit alone seems to determine thermodependence.

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Oocyte maturation in the amago salmon (Oncorhynchus rhodurus): In vitro effects of salmon gonadotropin, steroids, and cyanoketone (an inhibitor of 3β‐hydroxy‐Δ⁵‐steroid dehydrogenase)

1982

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The effect of partially purified chinook salmon gonadotropin (SG-G100) and a number of steroids on the induction of germinal vesicle breakdown (GVBD) in amago salmon (Oncorhynchus rhodurus) oocytes (with intact follicle layers) was investigated in vitro. SG-G100 was effective only at the highest concentration tested (1 microgram/ml). 17 alpha,20 beta-Dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog) was the most potent maturation-inducing steroid tested, followed by 17 alpha-hydroxyprogesterone. Testosterone or deoxycorticosterone (DOC) enhanced the rate of GVBD in response to SG-G100. DOC also enhanced the response to 17 alpha,20 beta-diOHprog but testosterone was without effect, suggesting that DOC has a direct action on the oocyte while testosterone probably acts at the level of the follicle. Estradiol-17 beta had no effect on GVBD in response to SG-G100 or 17 alpha,20 beta-diOHprog. The action of SG-G100 was shown to be dependent on the synthesis of a second delta 4 steroidal mediator of maturation since cyanoketone, a specific inhibitor of 3 beta-hydroxy-delta 5-steroid dehydrogenase, completely abolished the maturational effects of the gonadotropin and pregnenolone but not delta 4 steroids. Radioimmunoassay of media in which oocytes were induced to mature in vitro with SG-G100 revealed significantly elevated levels of progesterone and 17 alpha,20 beta-diOHprog. Estradiol-17 beta levels, high in control media, were only elevated twofold by SG-G100. Levels of the two progestogens were extremely low or nondetectable in media in which oocytes were incubated with cyanoketone, while estradiol-17 beta levels remained high. These results are discussed in relation to other evidence indicating that 17 alpha,20 beta-diOHprog is the naturally occurring maturation-inducing steroid of amago salmon. The role of other steroid hormones, particularly the possible involvement of corticosteroids, in the control of final oocyte maturation in teleosts is explored.

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Hormonal regulation of in vivo and in vitro oocyte maturation in the catfish, Heteropneustes fossilis (bloch)

Cited by 76 publications

References 44 publications

Periovulatory changes in catfish ovarian oestradiol-17beta, oestrogen-2-hydroxylase and catechol-O-methyltransferase during GnRH analogue-induced ovulation and in vitro induction of oocyte maturation by catecholoestrogens

Periovulatory changes in catfish ovarian oestradiol-17beta, oestrogen-2-hydroxylase and catechol-O-methyltransferase during GnRH analogue-induced ovulation and in vitro induction of oocyte maturation by catecholoestrogens

Les hormones gonadotropes de l'hypophyse : biochimie et biologie comparées ; spécificité et évolution

Oocyte maturation in the amago salmon (Oncorhynchus rhodurus): In vitro effects of salmon gonadotropin, steroids, and cyanoketone (an inhibitor of 3β‐hydroxy‐Δ⁵‐steroid dehydrogenase)

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Hormonal regulation of in vivo and in vitro oocyte maturation in the catfish, Heteropneustes fossilis (bloch)

Cited by 76 publications

References 44 publications

Periovulatory changes in catfish ovarian oestradiol-17beta, oestrogen-2-hydroxylase and catechol-O-methyltransferase during GnRH analogue-induced ovulation and in vitro induction of oocyte maturation by catecholoestrogens

Periovulatory changes in catfish ovarian oestradiol-17beta, oestrogen-2-hydroxylase and catechol-O-methyltransferase during GnRH analogue-induced ovulation and in vitro induction of oocyte maturation by catecholoestrogens

Les hormones gonadotropes de l'hypophyse : biochimie et biologie comparées ; spécificité et évolution

Oocyte maturation in the amago salmon (Oncorhynchus rhodurus): In vitro effects of salmon gonadotropin, steroids, and cyanoketone (an inhibitor of 3β‐hydroxy‐Δ5‐steroid dehydrogenase)

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Oocyte maturation in the amago salmon (Oncorhynchus rhodurus): In vitro effects of salmon gonadotropin, steroids, and cyanoketone (an inhibitor of 3β‐hydroxy‐Δ⁵‐steroid dehydrogenase)