Effects of global warming on fish reproductive endocrine axis, with special emphasis in pejerrey Odontesthes bonariensis

2013 ◽  
Vol 192 ◽  
pp. 45-54 ◽  
Author(s):  
Leandro Andrés Miranda ◽  
Tomás Chalde ◽  
Mariano Elisio ◽  
Carlos Augusto Strüssmann
Keyword(s):  
Global Warming ◽  
Odontesthes Bonariensis ◽  
Reproductive Endocrine ◽  
Endocrine Axis

scholarly journals OR11-01 Using Kisspeptin to Predict Pubertal Outcomes for Youth With Pubertal Delay

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Yee-Ming Chan ◽  
Margaret Flynn Lippincott ◽  
Priscila Sales Barroso ◽  
Cielo Alleyn ◽  
Jill Brodsky ◽  
...  
Keyword(s):  
Inhibin B ◽  
Stimulation Test ◽  
Delayed Puberty ◽  
Laboratory Studies ◽  
Pubertal Delay ◽  
Gnrh Release ◽  
Reproductive Endocrine ◽  
Physical Examinations ◽  
Outcomes For Children ◽  
Endocrine Axis

Abstract Background: The management of youth presenting with delayed puberty is challenging because it can be difficult to predict which children will eventually progress through puberty and which children will not. We have previously shown that exogenous administration of the neuropeptide kisspeptin, which stimulates GnRH release, can be used to probe the integrity of the reproductive endocrine axis. We hypothesized that responses to kisspeptin could predict outcomes for individuals with pubertal delay. Methods: We conducted a longitudinal study of 16 children (3 girls and 13 boys) with delayed or stalled puberty who had undergone stimulation testing with kisspeptin and GnRH. Participants were followed with serial physical examinations and laboratory studies every six months for evidence of progression through puberty. Inhibin B was measured in boys. A subset of participants underwent exome sequencing. Results: “Kisspeptin responders” who had responded to kisspeptin with a rise in LH of 0.8 mIU/mL or greater all subsequently progressed through puberty (n = 8). In contrast, “kisspeptin nonresponders” who had exhibited LH responses to kisspeptin ≤0.4 mIU/mL all reached age 18 years without developing physical signs of puberty (n = 8). Thus, responses to kisspeptin accurately predicted later pubertal outcomes (p = 0.0002), with sensitivity and specificity of 100% (95% CI 74-100%). Moreover, the kisspeptin-stimulation test outperformed overnight LH measurements, GnRH-stimulated LH, inhibin B, and genetic testing in predicting pubertal outcomes. Conclusion: The kisspeptin-stimulation test can be used to reveal future reproductive endocrine potential in prepubertal children and is a promising novel tool for predicting pubertal outcomes for children with delayed puberty. Trial registration: ClinicalTrials.gov NCT01438034

scholarly journals Developing Predictive Approaches to Characterize Adaptive Responses of the Reproductive Endocrine Axis to Aromatase Inhibition: I. Data Generation in a Small Fish Model

2013 ◽  
Vol 133 (2) ◽  
pp. 225-233 ◽  
Author(s):  
Daniel L. Villeneuve ◽  
Miyuki Breen ◽  
David C. Bencic ◽  
Jenna E. Cavallin ◽  
Kathleen M. Jensen ◽  
...  
Keyword(s):  
Small Fish ◽  
Data Generation ◽  
Adaptive Responses ◽  
Aromatase Inhibition ◽  
Fish Model ◽  
Reproductive Endocrine ◽  
Predictive Approaches ◽  
Endocrine Axis

GnRHa-mediated stimulation of the reproductive endocrine axis in captive Atlantic bluefin tuna, Thunnus thynnus

2012 ◽  
Vol 175 (1) ◽  
pp. 55-64 ◽  
Author(s):  
H. Rosenfeld ◽  
C.C. Mylonas ◽  
C.R. Bridges ◽  
G. Heinisch ◽  
A. Corriero ◽  
...  
Keyword(s):  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Atlantic Bluefin Tuna ◽  
Reproductive Endocrine ◽  
Endocrine Axis ◽  
Stimulation Of

scholarly journals Leptin modulates fertility under the influence of elevated growth hormone as modeled in oMt1a-oGH transgenic mice

2004 ◽  
Vol 182 (3) ◽  
pp. 421-432 ◽  
Author(s):  
AD Thomas ◽  
JD Murray ◽  
AM Oberbauer
Keyword(s):  
Growth Hormone ◽  
Pregnancy Rate ◽  
Reproductive Function ◽  
Treatment Groups ◽  
Reproductive Axis ◽  
Reproductive Endocrine ◽  
Estrous Cyclicity ◽  
Plasma Leptin ◽  
Old Females ◽  
Endocrine Axis

Elevated growth hormone (GH) concentrations suppress reproductive function in a variety of species, although it is unclear whether GH directly suppresses reproductive performance, or whether GH activates other pathways to achieve these effects. The ovine metallothionein 1a-ovine GH (oMt1a-oGH) transgenic mouse has been used to model the effects of GH on both body composition and reproductive function. A recent report has documented increased leptin levels in obese oMt1a-oGH mice. Given the importance of leptin in modulation of the reproductive endocrine axis, as well as the reports documenting reduced leptin signal transduction in animals with elevated leptin levels, we hypothesized that high leptin concentrations in response to elevated GH would reduce fertility. To determine the effects of high circulating leptin levels on the reproductive endocrine axis, we assessed hypothalamic neuropeptide Y (NPY) and GnRH expression. At weaning, oMt1a-oGH transgenic (TG) and wild-type (WT) female mice were allocated to one of four treatment groups: oMt1a-oGH females chronically expressing the transgene (TG ON); oMt1a-oGH females expressing the transgene from 3 to 8 weeks of age (TG ON/OFF); WT females receiving the transgene stimulus from 3 to 8 weeks of age (WT ON/OFF); and WT females never receiving the transgene stimulus (WT OFF). Eight-week-old females were housed with males for a 2-week period, after which females were isolated from males and allowed to carry pregnancies to term. Body and gonadal fat pad (GFP) weights, along with plasma leptin concentrations, estrous cyclicity, pregnancy rate and litter characteristics, were recorded for each female. Chronic expression of the oMt1a-oGH transgene resulted in larger leaner mice, and inactivation of the transgene produced obese females. Pregnancy rate was reduced in TG ON females when compared with all other groups, and infertility was associated with elevated leptin levels. In addition, high leptin levels were associated with increased NPY expression, suggesting reduced leptin-signaling capacity, which may contribute to suppression of the reproductive axis in oGH animals.

scholarly journals Modeling the Male Reproductive Endocrine Axis: Potential Role for a Delay Mechanism in the Inhibitory Action of Gonadal Steroids on GnRH Pulse Frequency

Endocrinology ◽  
2016 ◽  
Vol 157 (5) ◽  
pp. 2080-2092 ◽  
Author(s):  
Teuku R. Ferasyi ◽  
P. Hugh R. Barrett ◽  
Dominique Blache ◽  
Graeme B. Martin
Keyword(s):  
Negative Feedback ◽  
Time Delays ◽  
Model Development ◽  
Computer Software ◽  
Critical Factor ◽  
Pulse Frequency ◽  
Primary Control ◽  
Reproductive Endocrine ◽  
Endocrine Axis ◽  
Male Sheep

Abstract We developed a compartmental model so we could test mechanistic concepts in the control of the male reproductive endocrine axis. Using SAAM II computer software and a bank of experimental data from male sheep, we began by modeling GnRH-LH feed-forward and LH-T feedback. A key assumption was that the primary control signal comes from a hypothetical neural network (the PULSAR) that emits a digital (pulsatile) signal of variable frequency that drives GnRH secretion in square wave-like pulses. This model produced endocrine profiles that matched experimental observations for the testis-intact animal and for changes in GnRH pulse frequency after castration and T replacement. In the second stage of the model development, we introduced a delay in the negative feedback caused by the aromatization of T to estradiol at the brain level, a concept supported by empirical observations. The simulations showed how changes in the process of aromatization could affect the response of the pulsatile signal to inhibition by steroid feedback. The sensitivity of the PULSAR to estradiol was a critical factor, but the most striking observation was the effect of time delays. With longer delays, there was a reduction in the rate of aromatization and therefore a decrease in local estradiol concentrations, and the outcome was multiple-pulse events in the secretion of GnRH/LH, reflecting experimental observations. In conclusion, our model successfully emulates the GnRH-LH-T-GnRH loop, accommodates a pivotal role for central aromatization in negative feedback, and suggests that time delays in negative feedback are an important aspect of the control of GnRH pulse frequency.

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