Changes in brain gonadotropin‐releasing hormone, plasma estradiol 17‐β, and progesterone during the final reproductive cycle of the female sea lamprey, Petromyzon marinus

Bolduc, Thomas G.; Sower, Stacia A.

doi:10.1002/jez.1402640109

Cited by 43 publications

(21 citation statements)

References 23 publications

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“…The fish were processed for either RNA isolation or for in situ hybridization. Histological examination was performed as previously described [Fahien and Sower, 1990;Bolduc and Sower, 1992].…”

Section: Collection and Samplingmentioning

confidence: 99%

In situ Characterization of Gonadotropin- Releasing Hormone-I, -III, and Glutamic Acid Decarboxylase Expression in the Brain of the Sea Lamprey, Petromyzon marinus

et al. 2004

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The distribution of lamprey gonadotropin-releasing hormone (GnRH)-I and -III has been extensively characterized by immunocytochemistry in the forebrain of the sea lamprey, Petromyzon marinus. However, the cellular location of lamprey GnRH-III mRNA expression by in situ hybridization in the lamprey brain has not been determined. We show for the first time the location of expression of lamprey GnRH-III, as well as provide a more comprehensive in situ study of lamprey GnRH-I and glutamic acid decarboxylase (GAD; GABA-synthesizing enzyme) mRNA expression in the brain of the lamprey in different reproductive life stages. Colorimetric and dual-label fluorescent amplification methods of in situ hybridization were used on brain tissue sections of adult, juvenile, and larval sea lamprey. In each life stage of the lamprey, expression of lamprey GnRH-I was shown in the preoptic area (POA) and the hypothalamus forming the characteristic arc-like cell population extending from the preoptic nucleus (NPO) to the neurohypophysis. Lamprey GnRH-III expression was also seen in the POA of each life stage in close proximity to lamprey GnRH-I mRNA containing neurons. GAD expression was shown in distinct cell clusters in and around the POA, in the olfactory bulb, in the dorsal thalamus beneath the habenular region, and also in the ventral-medial hypothalamus stretching from the periventricular region to the anterior portion of the rhombencephalon. Using dual-label in situ hybridization, we have shown that lamprey GnRH-I and -III mRNA are colocalized in the same cells in the POA in adult lampreys. Dual-label in situ hybridization also showed close proximity of GAD mRNA containing neurons and GnRH containing neurons in the POA. These data suggest that γ-aminobutyric acid (GABA) may directly affect GnRH release in the brain of the sea lamprey.

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Section: Collection and Samplingmentioning

confidence: 99%

In situ Characterization of Gonadotropin- Releasing Hormone-I, -III, and Glutamic Acid Decarboxylase Expression in the Brain of the Sea Lamprey, Petromyzon marinus

et al. 2004

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“…In both the sea lamprey and Arctic lamprey (Lampetra camtschatica) E 2 concentrations increased during spermiation (Fukayama and Takahashi 1985;Sower et al 1985;Fahien and Sower 1990) and decreased during ovulation (Sower et al 1985;Linville et al 1987;Bolduc and Sower 1992). Our results showed higher concentrations of E 2 in fall males than spring males.…”

Section: Discussionmentioning

confidence: 39%

Sex steroids, gonadal histology and biological indices of fall and spring Caspian lamprey (Caspiomyzon wagneri) spawning migrants in the Shirud River, Southern Caspian Sea

et al. 2011

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This study investigates sex steroids, gonadal histology and some biological indices of fall and spring spawning migrants of Caspian lamprey Caspiomyzon wagneri (Kessler, 1870). Blood and gonad samples were collected from 15 migrants during fall and spring. Serum sex steroid levels including testosterone (T), 17β-estradiol (E 2 ) and progesterone (P) were determined with ELISA and gonadal development was studied using conventional histological methods. Our results showed serum E 2 level in females were similar in the two seasons but in males, fall migrants had higher serum E 2 concentrations. No differences were found in T levels in fall and spring migrants. Serum P concentration in fall migrant males were significantly higher than spring migrant males while spring migrant females had higher serum P levels compare to fall migrant females. Gonads in both fall and spring migrants were in the final stage of maturity. Fall and spring migrant males had similar HSI and GSI; fall migratory female had significantly higher HSI and GSI. Sex ratios were close to 1:1 in both seasons. There was a significant relationship between fecundity and length in both seasons. Comparison of fecundity and egg diameter between fall and spring seasons showed no significant difference. These results indicate that both fall and spring migrants Caspian lamprey were ready for spawning. Further studies are needed to clarify when spawning occurs in Caspian lamprey.

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“…In general, levels of estrogen, particularly 17-estradiols, are shown to increase gradually as oogenesis progresses (Prayogo, et al, 2012, Schulz et al, 2010. Thomas et al (2005) reported that circulating levels of estradiol in fish increased in correlation with an increase in the gonadosomatic index (GSI) and progression of oogenesis, suggesting their involvement in the acceleration of oogenesis in fish. Inhibiting the action of estradiol will decreasing GSI level and oogenesis progression.…”

Section: Discussionmentioning

confidence: 99%

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Prayogo¹,

Siregar²,

Sukardi³

2016

Turk. J. Fish. Aquat. Sci.

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Reproductive activities in fish are regulated by several environmental and physiological factors. In many aquatic ecosystems, metal concentrations are higher than natural levels, because of constant metallic releases from agricultural sources, industries, and mining operations. Mercury is a toxic and persistent pollutant, which bioaccumulates in the food chain. To investigate the effect of mercury chloride (HgCl) on fish reproduction, animals were keep with four aquaria containing increasing levels of HgCL (0 mg The effects of HgCl on reproduction performance on silver sharkminnow were evaluated by cGnRH-II and sGnRH gene expression, estradiol levels, GSI levels and proportion of oocyt. A significant decrease in by cGnRH-II and sGnRH gene expression, estradiol levels, GSI levels and proportion of oocyt were detected in fish receiving high mercury dose compared to controls on weeks 2,4,6, and 8 (P<0.05). On weeks 4, 6 and 8, all treatment groups had significantly lower cGnRH-II and sGnRH gene expression, estradiol levels, GSI levels and proportion of oocyt compared to the control group (P<0.05). These findings demonstrate a disruptive role of Mercury on the reproduction performance in Silver sharkminnow.

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Changes in brain gonadotropin‐releasing hormone, plasma estradiol 17‐β, and progesterone during the final reproductive cycle of the female sea lamprey, Petromyzon marinus

Cited by 43 publications

References 23 publications

In situ Characterization of Gonadotropin- Releasing Hormone-I, -III, and Glutamic Acid Decarboxylase Expression in the Brain of the Sea Lamprey, <i>Petromyzon marinus</i>

In situ Characterization of Gonadotropin- Releasing Hormone-I, -III, and Glutamic Acid Decarboxylase Expression in the Brain of the Sea Lamprey, <i>Petromyzon marinus</i>

Sex steroids, gonadal histology and biological indices of fall and spring Caspian lamprey (Caspiomyzon wagneri) spawning migrants in the Shirud River, Southern Caspian Sea

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