Insulin-Like Growth Factor I: A Possible Metabolic Signal Involved in the Regulation of Female Puberty

Hiney, Jill K.; Ojeda, Sergio R.; Dees, W. Les

doi:10.1159/000125924

Cited by 195 publications

(143 citation statements)

References 16 publications

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“…Thus, hGH could induce precocious puberty without changing growth rate in this Line. Under normal laboratory conditions, the age at vaginal opening is known to correlate nicely with body weight [30], suggesting that some metabolic factor signals the onset of puberty [30,31]. Line 2 transgenic female rats would be a good model for investigating that metabolic factor, if any, because growth promoting and puberty enhancing activities are separated in this animal model.…”

Section: Resultsmentioning

confidence: 99%

Changes in Endogenous Growth Hormone Secretion and Onset of Puberty in Transgenic Rats Expressing Human Growth Hormone Gene.

et al. 1994

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Abstract.A chimeric gene comprising murine whey acidic protein (mWAP) and human growth hormone (hGH) was used to produce transgenic rats that express hGH and secrete it into the blood. Two lines of transgenic rats carrying the mWAP/hGH construct were established: Line 1 was characterized by relatively high levels of serum hGH, and Line 2 had relatively low levels. The secretory profiles of rat GH (rGH) as well as hGH, the transgene product, were obtained in transgenic males and females of Line 2; both hGH and rGH serum levels were flattened with no episodic fluctuations, and the overall mean concentration of rGH was significantly lower than in normal littermates. Although the animals of Line 1 showed an accelerated increase in growth rate, those of Line 2 did not. Nevertheless, the onset of puberty in females, as assessed by vaginal opening and occurrence of first ovulation, advanced by 7-8 days in both Lines of animals.Accordingly, the body weight at puberty of Line 2 transgenic females was much lower than that of normal littermates, indicating that continuous hGH expression could induce precocious puberty without enhancing the growth rate.

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Section: Resultsmentioning

confidence: 99%

Changes in Endogenous Growth Hormone Secretion and Onset of Puberty in Transgenic Rats Expressing Human Growth Hormone Gene.

et al. 1994

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“…Neurotrophic factors may also play a similar role, and I would like to propose the hypothalamic insulin-like growth factor-1 (IGF-1) system as a target for neuroendocrine disruption. My laboratory and others have shown that IGF-1 regulates GnRH release and gene expression, and that this is subject to developmental regulation [74,75,37]. The IGF-1 system is also steroid sensitive [75,48,101].…”

Section: Other Hypothalamic Neurotransmitter and Neurotrophic Factor mentioning

confidence: 97%

Developmental programming and endocrine disruptor effects on reproductive neuroendocrine systems

Gore¹

2008

Frontiers in Neuroendocrinology

230

122

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The ability of a species to reproduce successfully requires the careful orchestration of developmental processes during critical time points, particularly the late embryonic and early postnatal periods. This article begins with a brief presentation of the evidence for how gonadal steroid hormones exert these imprinting effects upon the morphology of sexually differentiated hypothalamic brain regions, the mechanisms underlying these effects, and their implications in adulthood. Then, I review the evidence that aberrant exposure to hormonally-active substances such as exogenous endocrine-disrupting chemicals (EDCs), may result in improper hypothalamic programming, thereby decreasing reproductive success in adulthood. The field of endocrine disruption has shed new light on the discipline of basic reproductive neuroendocrinology through studies on how early life exposures to EDCs may alter gene expression via non-genomic, epigenetic mechanisms, including DNA methylation and histone acetylation. Importantly, these effects may be transmitted to future generations if the germline is affected via transgenerational, epigenetic actions. By understanding the mechanisms by which natural hormones and xenobiotics affect reproductive neuroendocrine systems, we will gain a better understanding of normal developmental processes, as well as to develop the potential ability to intervene when development is disrupted.

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“…IGF-I is involved in modulating hypothalamus and pituitary functions [28,42,71,85,91,92]. Several biological actions induced by IGF-I on GnRH and gonadotropin have been elucidated by a number of in vitro studies [53,95].…”

Section: Igf-i and Hypothalamo-pituitary Functionmentioning

confidence: 99%

Insulin-Like Growth Factor-I as a Possible Hormonal Mediator of Nutritional Regulation of Reproduction in Cattle

Zulu

Nakao

Sawamukai

2002

The Journal of Veterinary Medical Science

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ABSTRACT. The current review aims to establish insulin-like growth factor-1 (IGF-I) as the factor that signals nutritional status to the reproductive axis, and show that assessment of IGF-I in blood early postpartum during the negative energy balance (NEB) period could be used to predict both nutritional and reproductive status in dairy cattle. The review also explores the effect of nutritional status on circulating IGF-I concentrations and the endocrine role of IGF-I on the reproductive axis. IGF-I plays an important role in gonadotropininduced folliculogenesis, ovarian steroidogenesis and corpus luteum (CL) function. It also modulates pituitary and hypothalamus function. IGF-I clearly has an endocrine role on the reproductive axis. Severe under nutrition significantly reduces plasma IGF-I concentrations. During the critical period of NEB in high yielding dairy cattle early postpartum, IGF-I concentrations are low in blood and its levels are positively correlated to energy status and reproductive function during this period. Changes in circulating IGF-I immediately postpartum may help predict both nutritional and reproductive status in dairy cattle. IGF-I is therefore one of the long sought factors that signal nutritional status to the reproductive axis.

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Insulin-Like Growth Factor I: A Possible Metabolic Signal Involved in the Regulation of Female Puberty

Cited by 195 publications

References 16 publications

Changes in Endogenous Growth Hormone Secretion and Onset of Puberty in Transgenic Rats Expressing Human Growth Hormone Gene.

Changes in Endogenous Growth Hormone Secretion and Onset of Puberty in Transgenic Rats Expressing Human Growth Hormone Gene.

Developmental programming and endocrine disruptor effects on reproductive neuroendocrine systems

Insulin-Like Growth Factor-I as a Possible Hormonal Mediator of Nutritional Regulation of Reproduction in Cattle

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