Short photoperiod and testosterone-induced modification of GnRH release from the hypothalamus of Peromyscus maniculatus

Mintz, Eric M.; Lavenburg, Kim R.; Blank, James L.

doi:10.1016/j.brainres.2007.08.083

Cited by 10 publications

(11 citation statements)

References 31 publications

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“…Results from our population of white-footed mice (19) and from studies on a population of deer mice (Peromyscus maniculatus) by Blank and colleagues (3,29) indicate substantial genetic variation in reproductive photoresponsiveness within natural populations. In white-footed mice, this study shows genetic variation in levels of LH (Fig.…”

Section: Discussionmentioning

confidence: 68%

“…3) that is correlated with genetic variation in reproductive photoresponsiveness. In the deer mouse population studied by Blank and colleagues, phenotypic variation in reproductive photoresponsiveness was also correlated with variation in levels of LH, with indirect evidence that the phenotypic variation has an underlying genetic basis (3,29). Both sets of studies suggest that variation in levels of LH may be a cause of variation in reproductive function in wild populations.…”

Section: Discussionmentioning

confidence: 95%

“…Both sets of studies suggest that variation in levels of LH may be a cause of variation in reproductive function in wild populations. Furthermore, in both species there is variation in the GnRH neuron system that is a plausible cause for variation in levels of LH (1,3,29). However, many other factors also affect circulating levels of LH, including clearance rate, sensitivity of the pituitary to GnRH stimulation, number and secretory capacity of LH-secreting cells, and negative feedback directly on the pituitary (see Refs.…”

Section: Discussionmentioning

confidence: 99%

“…Natural populations of temperate-zone rodents contain substantial functional and genetic interindividual variation in this trait (5,8,10,17,19,33). Interindividual variation in the GnRH neuronal system has been correlated with variation in reproductive suppression (1,18,29), suggesting that variation in the GnRH neuronal system is related to interindividual variation in reproductive suppression in winter. Because GnRH neurons control LH secretion, interindividual variation in level of LH is a functional mechanism by which genetic variation in the HPG axis could directly affect reproductive phenotype.…”

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confidence: 99%

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Variation in levels of luteinizing hormone and reproductive photoresponsiveness in a population of white-footed mice (Peromyscus leucopus)

Heideman

Pittman

Schubert

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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Natural genetic variation in reproduction and life history strategies is a manifestation of variation in underlying regulatory neuronal and endocrine systems. A test of the hypothesis that genetic variation in luteinizing hormone (LH) level could be related to a life history trait, seasonal reproduction, was conducted on artificial selection lines from a wild-source population of white-footed mice (Peromyscus leucopus). Variation exists in the degree of suppression of reproduction by winter short-day photoperiods (SD) in wild-source individuals and in the laboratory population. In this population, most individuals from a photoperiod-responsive (R) artificial selection line are strongly suppressed reproductively in SD, while most individuals from a photoperiod-nonresponsive (NR) artificial selection line are only weakly reproductively suppressed in SD. We assayed levels of LH to test for genetic variation between lines that could contribute to variation in reproductive status in SD. Females from both lines were raised in long-day photoperiods (LD) or SD, ovariectomized under isoflurane anesthesia, and given estradiol implants. Levels of LH were significantly higher in the NR line than in the R line, indicating genetic variation for levels of LH. Levels of LH were higher in LD than in SD, indicating that levels of LH were sensitive to photoperiod treatment even with a controlled level of estradiol negative feedback. The results indicate that there is genetic variation in levels of LH that could be functionally important both in the laboratory in SD and in the wild population in winter. Thus genetic variation in levels of LH is a plausible causal factor determining winter reproductive phenotype in the wild population.

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Section: Discussionmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Variation in levels of luteinizing hormone and reproductive photoresponsiveness in a population of white-footed mice (Peromyscus leucopus)

Heideman

Pittman

Schubert

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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“…In many populations, some individuals show complete phenotypic plasticity by fully suppressing gametogenesis and reproduction in winter, some are intermediate, and others lack phenotypic plasticity, showing no response to short photoperiod (Bronson, 1989; Bronson & Heideman, 1994; Prendergast et al, 2001). The variation in response to short photoperiod has a genetic basis (Desjardins, Bronson & Blank, 1986; Heideman & Pittman, 2009; Prendergast et al, 2001), including genetic variation in gonadal development and in physiological traits in the reproductive neurons and hormones of the hypothalamic–pituitary–gonadal (HPG) axis (Blank & Ruf, 1992; Heideman & Pittman, 2009; Mintz, Lavenburg & Blank, 2007; Prendergast et al, 2001). An important question is whether there is genetic variation in behaviour that is related to variation in the development of reproductive organs and availability of gametes, and whether behavioural and morphological variation might cause differences in the number of offspring and size of litters.…”

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confidence: 99%

Genetic variation in male sexual behaviour in a population of white-footed mice in relation to photoperiod

et al. 2015

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In natural populations, genetic variation in seasonal male sexual behaviour could affect behavioural ecology and evolution. In a wild-source population of white-footed mice, Peromyscus leucopus, from Virginia, U.S.A., males experiencing short photoperiod show high levels of genetic variation in reproductive organ mass and neuroendocrine traits related to fertility. We tested whether males from two divergent selection lines, one that strongly suppresses fertility under short photoperiod (responder) and one that weakly suppresses fertility under short photoperiod (nonresponder), also differ in photoperiod-dependent sexual behaviour and responses to female olfactory cues. Under short, but not long, photoperiod, there were significant differences between responder and nonresponder males in sexual behaviour and likelihood of inseminating a female. Males that were severely oligospermic or azoospermic under short photoperiod failed to display sexual behaviour in response to an ovariectomized and hormonally primed receptive female. However, on the day following testing, females were positive for spermatozoa only when paired with a male having a sperm count in the normal range for males under long photoperiod. Males from the nonresponder line showed accelerated reproductive development under short photoperiod in response to urine-soiled bedding from females, but males from the responder line did not. The results indicate genetic variation in sexual behaviour that is expressed under short, but not long, photoperiod, and indicate a potential link between heritable neuroendocrine variation and male sexual behaviour. In winter in a natural population, this heritable behavioural variation could affect fitness, seasonal life history trade-offs and population growth.

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Genetic variation in total number and locations of GnRH neurons identified using in situ hybridization in a wild-source population

et al. 2015

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The evolution of brain function in the regulation of physiology may depend in part upon the numbers and locations of neurons. Wild populations of rodents contain natural genetic variation in the inhibition of reproduction by winter-like short photoperiod, and it has been hypothesized that this functional variation might be due in part to heritable variation in the numbers or location of gonadotropin releasing hormone (GnRH) neurons. A naturally variable wild-source population of white-footed mice was used to develop lines artificially selected for or against mature gonads in short, winter-like photoperiods. We compared a selection line that is reproductively inhibited in short photoperiod (Responsive) to a line that is weakly inhibited by short photoperiod (Nonresponsive) for differences in counts of neurons identified using in situ hybridization for GnRH mRNA. There was no effect of photoperiod, but there were 60% more GnRH neurons in total in the Nonresponsive selection line than the Responsive selection line. The lines differed specifically in numbers of GnRH neurons in more anterior regions, whereas numbers of GnRH neurons in posterior areas were not statistically different between lines. We compare these results to those of an earlier study that used immunohistochemical labeling for GnRH neurons. The results are consistent with the hypothesis that the selection lines and natural source population contain significant genetic variation in the number and location of GnRH neurons. The variation in GnRH neurons may contribute to functional variation in fertility that occurs in short photoperiods in the laboratory and in the wild source population in winter.

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Short photoperiod and testosterone-induced modification of GnRH release from the hypothalamus of Peromyscus maniculatus

Cited by 10 publications

References 31 publications

Variation in levels of luteinizing hormone and reproductive photoresponsiveness in a population of white-footed mice (Peromyscus leucopus)

Variation in levels of luteinizing hormone and reproductive photoresponsiveness in a population of white-footed mice (Peromyscus leucopus)

Genetic variation in male sexual behaviour in a population of white-footed mice in relation to photoperiod

Genetic variation in total number and locations of GnRH neurons identified using in situ hybridization in a wild-source population

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