In vitro effect of a fish gonadotropin on aromatase and 17 β-hydroxysteroid dehydrogenase activities in the ovary of the rainbow trout (Salmo gairdneri Rich.)

Sire, Olivier; Dépêche, J.

doi:10.1051/rnd:19810511

Cited by 18 publications

(8 citation statements)

References 8 publications

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“…A tritiated water release assay was used to measure aromatase activity, as previously described (Fostier, 1995). Androstenedione was chosen as a precursor due to its higher metabolization efficiency by trout ovarian aromatase, in comparison to testosterone (Sire and Depeche, 1981). One hundred rainbow trout follicles, 100 oocyte extracts, and 100 corresponding follicular layers were homogenized on ice in 8 ml phosphate buffer pH 7.55 using an Ultra‐Turrax.…”

Section: Methodsmentioning

confidence: 99%

Aromatase is expressed and active in the rainbow trout oocyte during final oocyte maturation

Gohin

Bodinier²,

Fostier³

et al. 2011

Molecular Reproduction Devel

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While it is generally well accepted that the ovarian follicular sites of estradiol-17β (E2) synthesis are restricted to somatic cells, the possible contribution of the germinal compartment has received little or no attention in teleosts. In order to demonstrate the expression of ovarian aromatase in the oocyte, cyp19a1a mRNA was studied in ovarian follicles by in situ hybridization. In addition, the expression of cyp19a1a was studied in both somatic and germinal compartments of the ovarian follicle in rainbow trout (Oncorhynchus mykiss) during final oocyte maturation (i.e., maturational competence acquisition and subsequent meiosis resumption) by real-time PCR. The enzymatic activity of ovarian aromatase was also studied in both somatic and germinal compartments of the ovarian follicle. Finally, E2 levels were monitored in follicle-enclosed oocytes throughout the pre-ovulatory period. We were able to demonstrate a significant ovarian aromatase expression and activity in the late vitellogenic oocyte. Furthermore, a dramatic decrease in aromatase expression and activity occurs in the oocyte during late oogenesis, concomitantly with the trend observed in surrounding follicular layers. We also report an unexpected increase of E2 levels in the oocyte during the pre-ovulatory period. To our knowledge, these observations are reported for the first time in any teleost species. Together, our data support the hypothesis of the participation of the germinal compartment in follicular estrogen synthesis and a biological role of E2 during oocyte and/or early embryo development.

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Section: Methodsmentioning

confidence: 99%

Aromatase is expressed and active in the rainbow trout oocyte during final oocyte maturation

Gohin

Bodinier²,

Fostier³

et al. 2011

Molecular Reproduction Devel

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“…Working with amago salmon Kagawa et al (1982) and Young et al ( , 1983 have suggested that a twocell process of oestradiol biosynthesis may operate in which androgens synthesized by the theca are transformed to oestrogens by aromatase action in the granulosa. Sire and Depeche (1981) have also shown that gonadotrophin inhibited aromatase activity in rainbow trout ovaries incubated in vitro. By contrast, the GTH stimulated granulosa preparation produced a small amount of oestradiol (max 4 ng/ml, Fig.…”

Section: Discussionmentioning

confidence: 84%

“…Indeed, Jalabert (1975) has shown that oestradiol exerts some inhibitory influence on the gonadotrophin induced maturation of rainbow trout follicles in vitro. In teleosts as in other vertebrate classes C19 androgenic steroids, serving as substrated for aromatase enzymes are the precursors of oestrogens (Sire and Depeche 1981;Fostier et al 1983). Interest in its biosynthesis during oocyte final maturation then stems principally from the better understanding which may accrue of the rapidly changing pattern of steroid hormone synthesis which occurs at this time.…”

Section: Discussionmentioning

confidence: 99%

Steroid release from separated theca and granulosa layers of Atlantic salmon (Salmo salar) ovarian follicles: the effects of a purified salmon gonadotrophin preparation

Wright

Zhao²

1988

Fish Physiol Biochem

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Theca and granulosa layers were removed from ovarian follicles of mature Atlantic salmon (Salmo salar) and were separately incubated under sterile conditions with and without a partially purified salmon gonadotrophin preparation (GTH). Aliquots of the incubation media were removed at intervals and analysed for the steroids 17α, 20β-dihydroxy-4-pregnen-3-one (17α20βP), 17α-hydroxyprogesterone, progesterone, androstenedione, testosterone and oestradiol. The biosynthesis of C19 and C21 steroids was very largely restricted to the thecal tissue and was markedly stimulated in the presence of GTH. Androstenedione (max 65 ng/ml) and testosterone (max 14 ng/ml) were released from the earliest stages of incubation whereas the release of 17α-hydroxyprogesterone (max 51 ng/ml) and progesterone (max 5.5 ng/ml) commenced only after a lengthy induction period. A trace (1.0 ng/ml) of 17α20βP was produced by the theca in the presence of GTH but oestradiol was not detected. The granulosa preparations released levels of 17α-hydroxyprogesterone and androstenedione only marginally above the detection limits (ca 0.7 ng/ml) and there was little stimulation of output with GTH. Oestradiol (max 4 ng/ml) was released only in the presence of GTH. 17α20βP, progesterone and testosterone were not detected as products of this tissue. These results, together with those derived earlier from incubations of complete follicles support the view that the synthesis of 17α20βP is essentially a two-cell process in which 17α-hydroxyprogesterone produced in the theca is subject to the action of steroid 20β-hydroxysteroid dehydrogenase in the granulosa. The temporal pattern of release of steroids in these and earlier experiments is considered in relation to mechanisms of steroid biosynthesis and to their possible roles in oocyte final maturation.

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“…As their expression in the differentiating ovary is high at a time when testosterone and 17β‐estradiol metabolism is active (Petkam et al, ), Shbgb could serve to protect both from being degraded. Shbgb could also restrict the availability of testosterone as a substrate for aromatase, leaving the alternative substrate, androstenedione (Sire and Dépêche, ), more available for conversion by the enzyme. Other Shbgb functions involving the mechanism of action of sex steroids during the ovarian differentiation could exist (Caldwell and Jirikowski, ), and need to be further investigated.…”

Section: Discussionmentioning

confidence: 99%

Sex hormone‐binding globulins characterization and gonadal gene expression during sex differentiation in the rainbow trout, Oncorhynchus mykiss

Marivin

Yano

Guérin

et al. 2014

Molecular Reproduction Devel

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Sex hormone-binding globulin (SHBG) binds androgens and estrogens in the blood of many vertebrates, including teleost fish. In mammals, SHBG is synthetized in the liver and secreted into the blood. In fish, shbga also exhibits a hepatic expression. In salmonids, in which the gene has been duplicated, the recently discovered shbgb gene exhibits a predominantly ovarian expression. The present work aimed at gaining new insight into shbgb gene structure and expression during gonadal sex differentiation, a steroid-sensitive process, and Shbgb protein structure and binding characteristics; specifically, rainbow trout (Oncorhynchus mykiss) shbgb was analyzed. shbgb structure was analyzed in silico while expression was characterized during gonadal sex differentiation using all-male and all-female populations. We observed that shbgb gene and cognate-protein structures are similar to homologs previously described in zebrafish and mammals. The shbgb gene is predominantly expressed in differentiating female gonads, with increased expression around the end of ovarian differentiation. In the ovary, shbgb mRNA was detected in a subset of somatic cells surrounding the ovarian lamellae. Furthermore, Shbgb binds steroids with a higher selectivity than Shbga, exhibiting a higher affinity for estradiol compared to Shbga. In conclusion, Shbgb binding characteristics are clearly different from those of Shbga. Shbgb is expressed in the differentiating ovary during a period when the synthesis and action of testosterone and estradiol must be tightly regulated. This strongly suggests that Shbgb participates in the regulation of steroid metabolism and/or mediation, that is, needed during early gonadal development in rainbow trout.

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In vitro effect of a fish gonadotropin on aromatase and 17 β-hydroxysteroid dehydrogenase activities in the ovary of the rainbow trout (Salmo gairdneri Rich.)

Cited by 18 publications

References 8 publications

Aromatase is expressed and active in the rainbow trout oocyte during final oocyte maturation

Aromatase is expressed and active in the rainbow trout oocyte during final oocyte maturation

Steroid release from separated theca and granulosa layers of Atlantic salmon (Salmo salar) ovarian follicles: the effects of a purified salmon gonadotrophin preparation

Sex hormone‐binding globulins characterization and gonadal gene expression during sex differentiation in the rainbow trout, Oncorhynchus mykiss

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