Brain distribution of radioimmunoassayable gonadotropin-releasing hormone in female goldfish: Seasonal variation and periovulatory changes

Yu, Kei Li; Nahorniak, Carol S.; Peter, Richard; Corrigan, A; Rivier, Jean; Vale, Wylie

doi:10.1016/0016-6480(87)90153-5

Cited by 89 publications

(35 citation statements)

References 26 publications

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“…The most parsimonious explanation of our data is that a single population of androgensensitive SPI-ir neurons provides innervation to all the sexually dimorphic diencephalic nuclei. Similar hypotheses has been made for other peptide systems in teleosts (Yu et al, 1987;Oka and Matsushima, 1993).…”

Section: Androgen-induced Changes In Spi-irmentioning

confidence: 50%

Androgen-induced changes in electrocommunicatory behavior are correlated with changes in substance P-like immunoreactivity in the brain of the electric fish Apteronotus leptorhynchus

1995

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The hormonal regulation of sex differences in electrocommunicatory behavior and brain substance P-like immunoreactivity (SPI-ir) were examined in the weakly electric fish, Apteronotus leptorhynchus. This animal modulates its electric organ discharge (EOD) to produce discrete electric social signals (chirps), which function in aggressive and reproductive displays. Males readily chirp in response to electrosensory stimuli that mimic the presence of a conspecific; females also chirp in response to such stimuli, but do so at much lower rates than males. We have recently demonstrated that androgen treatment enhances chirping behavior in females and may also lead to a change in chirp quality or structure. In this study, we quantified androgen- induced changes in chirp structure and simultaneously examined whether androgens alter the sexually dimorphic pattern of SPI-ir in a brain region (prepacemaker nucleus, PPn) known to control chirping. Our results demonstrate that, in females, androgens cause both the induction of chirping and an alteration of chirp structure; chirps recorded from androgen-implanted females had longer durations and more dramatic frequency and amplitude modulations compared to controls, and appear similar to those reported to be produced during spawning. Moreover, androgen-induced changes in chirping are correlated with increased expression of SPI-ir within specific brain nuclei of females. These changes may underly behavioral changes in chirping, since treated females showed a male-like pattern of SPI-ir in the PPn. However, alterations in SPI-ir were not restricted to the PPn, but also occurred in diencephalic regions related to pituitary function and reproductive behavior. The results suggest that androgens modulate chirping activity and cause both specific and wide-spread changes in SPI-ir that may relate to a functional system that interrelates pituitary function, reproductive behavior, and chirping.

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Section: Androgen-induced Changes In Spi-irmentioning

confidence: 50%

Androgen-induced changes in electrocommunicatory behavior are correlated with changes in substance P-like immunoreactivity in the brain of the electric fish Apteronotus leptorhynchus

1995

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“…For instance, in the masu salmon, Oncorhynchus masou, pituitary GnRH levels are low in juvenile animals, but the levels increase during puberty when the gonads start to increase in size and the processes of vitellogenesis and spermatogenesis are initiated (Amano et al 1992(Amano et al , 1993. Elevated pituitary GnRH levels are likely to be the result of an increased GnRHsynthesizing activity; however, clear correlations between brain GnRH levels and gonadal maturation cannot always be detected (Yu et al 1987, Okuzawa et al 1990, Amano et al 1993. This lack of correlation may be related to the involvement of GnRH in non-pituitary-related processes by acting as a neurotransmitter and/or neuromodulator elsewhere in the brain (Oka 1997).…”

Section: Introductionmentioning

confidence: 99%

Seasonal fluctuations in pituitary levels of the three forms of gonadotropin-releasing hormone in striped bass, Morone saxatilis (Teleostei), during juvenile and pubertal development

Holland¹,

Hassin²,

Zohar³

2001

Journal of Endocrinology

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In most vertebrates, the development of a mature gonadotropin-releasing hormone (GnRH) secretory system is pivotal for the onset of puberty. The role of the three native GnRH forms, seabream (sb) GnRH, chicken (c) GnRH-II and salmon GnRH, in striped bass puberty remains elusive. This study examined the changes in pituitary GnRH levels throughout juvenile and pubertal development, a period encompassing 3 to 4 years. The levels of the two most abundant forms in the pituitary, sbGnRH and cGnRH-II (10:1), increased during the Fall and peaked prior to (cGnRH-II) or during (sbGnRH) the natural breeding season in March to May. In most cases, sbGnRH and cGnRH-II levels of maturing fish correlated to changes in oocyte diameter, gonadosomatic index and LH pituitary content. Interestingly, pituitaries of immature and maturing 2-and 3-year-old males and females contained similar amounts of all three GnRH forms. Additionally, pituitary sbGnRH and cGnRH-II levels in juvenile fish were relatively high and GnRH profiles showed a clear seasonality, similar to those of older, mature fish. These findings suggest a role for both sbGnRH and cGnRH-II in the regulation of gonadal development and indicate that, unlike some mammalian species, the timing of puberty in striped bass is not limited by a low activity of the GnRH system.

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“…In fish brain and pituitary, the GnRH levels remain low in juveniles, increase in adults (Rosenblum et al 1994) and peak when fish reach maturity. This is the case in the brown trout (Breton et al 1986), goldfish (Yu et al 1987) and roach (Breton et al 1988). In the absence of a hypothalamo-pituitary portal system, sGnRH during this period accumulates mainly in the pituitary, the contents of which are higher than in the brain (Breton et al 1986(Breton et al , 1988.…”

Section: Physiological Effect Of Sgnrh-antisense Expressionmentioning

confidence: 99%

Transgenic rainbow trout expressed sGnRH-antisense RNA under the control of sGnRH promoter of Atlantic salmon

Uzbekova¹,

Chyb²,

Ferrière³

et al. 2000

Journal of Molecular Endocrinology

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A recombinant vector containing antisense DNA complementary to Atlantic salmon (Salmo salar) sGnRH cDNA driven by specific promoter Pab derived from a corresponding sGnRH gene was introduced into rainbow trout (Oncorhynchus mykiss) eggs. This resulted in transgenic animals that had integrated one copy of the transgene into their genome and transmitted it through the germline. Antisense-sGnRH mRNA (AS) was expressed mainly in the brain of transgenic AS(+) fish. Levels of sGnRH endogenous mRNA in the brain were lower in 11-month-old AS(+) fish compared with nontransgenic AS( ) individuals from the same F2 progeny. sGnRH levels significantly decreased in the pituitary of transgenic males and females around the maturation period and in the brain of AS(+) immature females compared with controls. No reliable statistical difference was found in the levels of FSH and LH between AS(+) and AS( ) groups either in immature or mature fish. The majority of transgenic fish reached maturity at the same time as did nontransgenic individuals, although the maturation of AS(+) animals seemed to be more asynchronous. For the first time, the influence of antisense messengers on endogenous mRNA in transgenic fish and the corresponding protein is described.

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Brain distribution of radioimmunoassayable gonadotropin-releasing hormone in female goldfish: Seasonal variation and periovulatory changes

Cited by 89 publications

References 26 publications

Androgen-induced changes in electrocommunicatory behavior are correlated with changes in substance P-like immunoreactivity in the brain of the electric fish Apteronotus leptorhynchus

Androgen-induced changes in electrocommunicatory behavior are correlated with changes in substance P-like immunoreactivity in the brain of the electric fish Apteronotus leptorhynchus

Seasonal fluctuations in pituitary levels of the three forms of gonadotropin-releasing hormone in striped bass, Morone saxatilis (Teleostei), during juvenile and pubertal development

Transgenic rainbow trout expressed sGnRH-antisense RNA under the control of sGnRH promoter of Atlantic salmon

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