Characterization and steroidal regulation of gonadotropin beta subunits in the male leopard frog, Rana pipiens

Zhang, Lihong; Kessler, Ann E.; Tsai, Pei‐San

doi:10.1016/j.ygcen.2006.07.006

Cited by 9 publications

(8 citation statements)

References 19 publications

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“…The FSH ␤ subunit exists in the GTH-producing cells of frog pituitary glands and is released from the cells to regulate the production of steroid hormones in the gonad [Gracia-Navarro and Licht, 1987;Tanaka et al, 1990]. The cDNA sequence of amphibian FSH ␤ has been determined in the newt Cynops pyrrhogaster [Saito et al, 2002] and the frog Rana pipiens [Zhang et al, 2007].…”

Section: Upregulation Of Fsh and Fsh Receptormentioning

confidence: 99%

Is a Sex-Determining Gene(s) Necessary for Sex-Determination in Amphibians? Steroid Hormones May Be the Key Factor

Nakamura¹

2012

Sex Dev

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Amphibians have 2 genetic sex-determining systems, one with male (XX/XY) and one with female (ZZ/ZW) heterogamety. While the ancestral state of sex-determination is thought to be female heterogamety, male and female heterogametic types were probably once interchangeable. The Japanese frog Rana rugosa has both XX/XY and ZZ/ZW systems within a single species in certain local populations. However, steroid hormones can alter the phenotypic sex epigenetically. In R. rugosa, steroidogenic enzyme expression starts before sex-determination in the indifferent gonad, and these enzymes become active in both male and female tadpoles. Androgens are produced in the indifferent gonad of male tadpoles at high levels, whereas estrogens are synthesized in females. In this regard, the observed enhanced expression of the hormone-metabolizing genes, CYP19 in the female gonad and CYP17 in males, may be crucial for sex-determination. Moreover, with FSH known to increase estrogen synthesis in the vertebrate ovary, observed upregulation of FSH receptor (FSHR) expression in the indifferent gonad of female tadpoles is intriguing. These data suggest that steroid hormones could be crucial for sex-determination in R. rugosa, with the consequence that upregulation of CYP19 and FSHR expression is necessary for female and CYP17 for male sex-determination.

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Section: Upregulation Of Fsh and Fsh Receptormentioning

confidence: 99%

Is a Sex-Determining Gene(s) Necessary for Sex-Determination in Amphibians? Steroid Hormones May Be the Key Factor

Nakamura¹

2012

Sex Dev

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“…In adult anurans, the impact of ED on the hypothalamic–pituitary complex has been shown in Rana pipiens where DHT and E2 adversely affect spermatogenesis, increase GnRH release, and decrease plasma levels of sex steroids and gene expression of LH 22–24 . Lower LH plasma levels following exposure to the estrogenic ED nonylphenol has been reported in R. esculenta.…”

Section: Reproductive Biology Of Amphibians and Fishmentioning

confidence: 99%

Endocrine Disruption in Aquatic Vertebrates

Kloas

Urbatzka

Opitz

et al. 2009

Annals of the New York Academy of Sciences

158

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Environmental compounds can interfere with endocrine systems of wildlife and humans. The main sink of such substances, called endocrine disrupters (ED), are surface waters. Thus, aquatic vertebrates, such as fish and amphibians, are most endangered. ED can adversely affect reproductive biology and the thyroid system. ED act by (anti)estrogenic and (anti)androgenic modes of action, resulting in abnormal sexual differentiation and impaired reproduction. These effects are mainly driven by direct interferences of ED with sex steroid receptors rather than indirectly by impacting synthesis and bioavailability of sex steroids, which in turn might affect the hypothalamic-pituitary-gonadal axis. Recent findings reveal that, in addition to the human-produced waste of ED, natural sources, such as parasites and decomposition of leaves, also might act as ED, markedly affecting sexual differentiation and reproduction in fish and amphibians. Although the thyroid system has essential functions in both fish and amphibians, amphibian metamorphosis has been introduced as the most sensitive model to detect thyroidal ED; no suitable fish model exists. Whereas ED may act primarily on only one specific endocrine target, all endocrine systems will eventually be deregulated as they are intimately connected to each other. The recent ecotoxicological issue of pharmaceutically active compounds (PhACs) present in the aquatic environment indicates a high potential for further endocrine modes of action on aquatic vertebrates by ED derived from PhACs, such as glucocorticoids, progestins, and beta-agonists.

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“…For both gonadotropins, ontological gene expression, specificity to the pituitary, and regulation have been described in Rana pipiens (Zhang et al, 2007). As noticed above, the regulation of gonadotropin secretion is primarily by GnRH.…”

Section: Gonadotropins In Amphibiansmentioning

confidence: 91%