The role of pituitary gonadotropins in gonadal sex differentiation in the protogynous Malabar grouper, Epinephelus malabaricus

Murata, Ryosuke; Kobayashi, Yasuhisa; Karimata, Hirofumi; Kishimoto, Kazuo; Kimura, Motofumi; Shimizu, Akio; Nakamura, Masaru

doi:10.1016/j.ygcen.2012.07.012

Cited by 21 publications

(10 citation statements)

References 39 publications

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“…In the honeycomb grouper, Epinephelus merra, sex change also was obtained with fadrozole after 13 weeks during the non-breeding season (Bhandari et al, 2004a), 11 weeks during the early pre-breeding season (Bhandari et al, 2004b) and 3 weeks during the spawning season (Alam et al, 2006a) and in protogynous wrasse, Halichoeres trimaculatus, after just 5 days (Nozu et al, 2009). In addition to the use of AI and synthetic androgens for promoting sex change in protogynous teleosts, some studies have shown that pituitary gonadotropins that modulate the synthesis of gonadal steroids in vertebrates (Norris, 2007) can also play a key role in this process (Zhang et al, 2007;Kobayashi et al, 2010;Murata et al, 2012). In the protandrous cinnamon clownfish, Amphiprion melanopus, the neurohormone gonadotropin-releasing hormone (GnRH) was also involved in the control of sex change (Kim et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Involvement of pituitary gonadotropins, gonadal steroids and breeding season in sex change of protogynous dusky grouper, Epinephelus marginatus (Teleostei: Serranidae), induced by a non-steroidal aromatase inhibitor

Garcia

Araújo

Mello

et al. 2013

General and Comparative Endocrinology

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Two experiments were performed using the aromatase inhibitor (AI) letrozole (100mg/kg) to promote sex change, from female-to-male, in protogynous dusky grouper. One experiment was performed during the breeding season (spring) and the other at the end of the breeding season (summer). During the spring, AI promoted sex change after 9 weeks and the sperm produced was able to fertilize grouper oocytes. During the summer, the sex change was incomplete; intersex individuals were present and sperm was not released by any of the animals. Sex changed gonads had a lamellar architecture; cysts of spermatocytes and spermatozoa in the lumen of the germinal compartment. In the spring, after 4 weeks, 11ketotestosterone (11KT) levels were higher in the AI than in control fish, and after 9 weeks, coincident with semen release, testosterone levels increased in the AI group, while 11KT returned to the initial levels. Estradiol (E2) levels remained unchanged during the experimental period. Instead of decreasing throughout the period, as in control group, 17 α-OH progesterone levels did not change in the AI-treated fish, resulting in higher values after 9 weeks when compared with control fish. fshβ and lhβ gene expression in the AI animals were lower compared with control fish after 9 weeks. The use of AI was effective to obtain functional males during the breeding season. The increase in androgens, modulated by gonadotropins, triggered the sex change, enabling the development of male germ cells, whereas a decrease in E2 levels was not required to change sex in dusky grouper.

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Section: Introductionmentioning

confidence: 99%

Involvement of pituitary gonadotropins, gonadal steroids and breeding season in sex change of protogynous dusky grouper, Epinephelus marginatus (Teleostei: Serranidae), induced by a non-steroidal aromatase inhibitor

Garcia

Araújo

Mello

et al. 2013

General and Comparative Endocrinology

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“…Similar result was observed in seven band grouper, exogenous FSH treatment stimulate ovarian growth in the post-spawning period (40). In red-spotted grouper ( Epinephelus akaara ) and Malabar grouper ( E. malabaricus ), fsh β was expressed before the onset of sex differentiation (21, 41). In addition, the expression of cyp19a1a was up-regulated after 2 weeks of FSH treatment.…”

Section: Discussionmentioning

confidence: 99%

“…In fact, FSH has been detected in the pituitary prior to the onset of gonadal sex differentiation in a variety of species (18–20). In the Malabar grouper ( Epinephelus malabaricus ), fsh β was present and significantly increased in concentration in the undifferentiated and ovarian differentiation stages, while lh β was not expressed before ovarian differentiation and was first detected after ovarian differentiation (21). These reports suggest that FSH may be involved in gonadal sex differentiation.…”

Section: Introductionmentioning

confidence: 99%

New Insights Into the Role of Follicle-Stimulating Hormone in Sex Differentiation of the Protogynous Orange-Spotted Grouper, Epinephelus coioides

et al. 2019

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Follicle-stimulating hormone (FSH) signaling is considered to be essential for early gametogenesis in teleosts, but its functional roles during sex differentiation are largely unknown. In this study, we investigated the effects of long-term and short-term FSH injection on sex differentiation in the protogynous orange-spotted grouper ( Epinephelus coioides ). Long-term FSH treatment initially promoted the formation of ovaries but subsequently induced a male fate. The expression of female pathway genes was initially increased but then decreased, whereas the expression of male pathway genes was up-regulated only during long-term FSH treatment. The genes related to the synthesis of sex steroid hormones, as well as serum 11-ketotestosterone and estradiol, were also up-regulated during long-term FSH treatment. Short-term FSH treatment activated genes in the female pathway (especially cyp19a1a ) at low doses but caused inhibition at high doses. Genes in the male pathway were up-regulated by high concentrations of FSH over the short term. Finally, we found that low, but not high, concentrations of FSH treatment activated cyp19a1a promoter activities in human embryonic kidney (HEK) 293 cells. Overall, our data suggested that FSH may induce ovarian differentiation or a change to a male sex fate in the protogynous orange-spotted grouper, and that these processes occurred in an FSH concentration-dependent manner.

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“…They are available for immunocytochemical and immunochemical assays for acanthopterygian fishes, and both FSH cells and LH cells in various species have been identified using the antisera (Fig. 40, Shimizu et al 2003a, b;Pandolfi et al 2006;Pham et al 2007;Kobayashi et al 2010;Nyuji et al 2011;Murata et al 2012). In addition, using these antisera, GtHs and their subunits have been successively purified from several species (Molés et al 2008;Ohga et al 2012;Nyuji et al 2013).…”

Section: -2g Applications To Other Percoid Fishesmentioning

confidence: 99%

Reproductive Physiology of the Mummichog <i>Fundulus heteroclitus</i>—An Excellent Experimental Fish

Shimizu¹

2014

Aqua-BioSci. Monogr. (ABSM)

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The mummichog is a euryhaline cyprinodont fish native to North America. In this monograph, various reproductive properties, i.e. gonadal changes during ontogeny, gonadal and endocrine changes during annual and daily reproductive cycles, and environmental and endocrine control of reproduction are described. This fish is a spring to summer spawner showing distinct annual changes in gonadal states. A reared strain of this fish shows daily spawning also indicating distinct cycles of oocyte development and maturation. Their annual reproductive cycle is precisely controlled by environmental factors, such as lowering temperature in autumn and winter, warm temperature in spring, and short photoperiod in early autumn. These factors induce the early phase of gonadal development, initiation of the spawning period, and termination of the spawning period, respectively. Their gonadotrophs (FSH cells and LH cells) showed prominent changes during the ontogeny and the annual reproductive cycle. FSH cells appeared at very early stages in the ontogeny, and their abundance showed good correlation to the gonadal stages in the annual cycle. LH cells appeared later, and were abundant only during the spawning period. Plasma FSH levels also showed good correlation to the gonadal stages, whereas plasma LH levels were high only during the spawning period. These findings indicate that FSH is important for gonadal development and LH is responsible for final gametes maturation. Such functional differentiation of GtHs is also indicated by studies on their receptors (FSHR and LHR). The above described researches show that the mummichog is an excellent model fish for studying environmental and endocrine control of reproductive cycles, especially for GtH related studies because of the presence of sufficient analyzing tools (specific antibodies, purified hormones, ELISA systems, receptors, etc.).

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The role of pituitary gonadotropins in gonadal sex differentiation in the protogynous Malabar grouper, Epinephelus malabaricus

Cited by 21 publications

References 39 publications

Involvement of pituitary gonadotropins, gonadal steroids and breeding season in sex change of protogynous dusky grouper, Epinephelus marginatus (Teleostei: Serranidae), induced by a non-steroidal aromatase inhibitor

Involvement of pituitary gonadotropins, gonadal steroids and breeding season in sex change of protogynous dusky grouper, Epinephelus marginatus (Teleostei: Serranidae), induced by a non-steroidal aromatase inhibitor

New Insights Into the Role of Follicle-Stimulating Hormone in Sex Differentiation of the Protogynous Orange-Spotted Grouper, Epinephelus coioides

Reproductive Physiology of the Mummichog <i>Fundulus heteroclitus</i>—An Excellent Experimental Fish

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