Vaginocervical Stimulation of Ferrets Induces Release of Luteinizing Hormone‐Releasing Hormone

Bibeau, Carole E.; Tobet, Stuart A.; Anthony, Edythe L. P.; Carroll, Rona S.; Baum, Michael J.; King, Joan C.

doi:10.1111/j.1365-2826.1991.tb00235.x

Cited by 23 publications

(8 citation statements)

References 24 publications

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“…In brown bats collected after ovulation, fewer GnRH-ir cell bodies are present as compared with brains collected ear lier in the season, prior to ovulation [54]. A similar find ing has been reported under controlled laboratory' condi tions in ferrets [40]. I lowever.…”

Section: Discussionsupporting

confidence: 56%

Interactions with Males Promote Rapid Changes in Gonadotropin-Releasing Hormone Immunoreactive Cells

1995

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It is well known that hormones can regulate behaviors. However, the reciprocal interaction, the effects of behavior on hormones, has received less direct experimental attention. Dramatic changes in hormones and behaviors occur at puberty and some of these changes can be triggered by modification of the social environment. Interactions with males accelerate production of pulsatile release of gonadotropins and steroid hormones which, in turn, initiate estrous cycles, ovulation, and sexual behavior in females. Ultimately all of these actions are controlled by changes in production and secretion of gonadotropin-releasing hormone (GnRH). Little is known about how behavior affects GnRH-producing neurons. In female musk shrews, the first mating initiates the onset of puberty. Musk shrews lack a behavioral estrous cycle and they become receptive within minutes after their first contact with a male. As soon as 1 h after interactions with males there is a significant increase in the numbers of GnRH-immunoreactive (GnRH-ir) neurons in specific brain regions. In the present study, we examined changes in GnRH-ir cell number during the initial mating bout. We found dynamic changes in the numbers of GnRH-containing cells, correlated with changes in behavior. Interactions with males for less than 30 minutes induced a significant increase in GnRH-ir neurons in specific olfactory-related forebrain nuclei. At the end of a mating bout, numbers of GnRH-ir neurons declined. Because behavioral interactions have rapid and pronounced effects on the neurons that produce GnRH, this model can be used to examine the behavioral regulation of neuronal plasticity.

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Section: Discussionsupporting

confidence: 56%

Interactions with Males Promote Rapid Changes in Gonadotropin-Releasing Hormone Immunoreactive Cells

1995

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“…There is additional, independent evidence (19) that MBH GnRH biosynthesis is regulated by posttranscriptional mechanisms in the ferret. The number of protein-synthesizing organelles, particularly Golgi complexes, was significantly increased in GnRH neurons of female ferrets that received vaginal-cervical stimulation.…”

Section: Neuronal Fos/gnrh Colocalizationmentioning

confidence: 99%

Neuroendocrine Regulation of GnRH Release in Induced Ovulators

Bakker

Baum

2000

Frontiers in Neuroendocrinology

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178

135

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GnRH is the key neuropeptide controlling reproductive function in all vertebrate species. Two different neuroendocrine mechanisms have evolved among female mammals to regulate the mediobasal hypothalamic (MBH) release of GnRH leading to the preovulatory secretion of LH by the anterior pituitary gland. In females of spontaneously ovulating species, including rats, mice, guinea pigs, sheep, monkeys, and women, ovarian steroids secreted by maturing ovarian follicles induce a pulsatile pattern of GnRH release in the median eminence that, in turn, stimulates a preovulatory LH surge. In females of induced ovulating species, including rabbits, ferrets, cats, and camels, the preovulatory release of GnRH, and the resultant preovulatory LH surge, is induced by the receipt of genital somatosensory stimuli during mating. Induced ovulators generally do not show "spontaneous" steroid-induced LH surges during their reproductive cycles, suggesting that the positive feedback actions of steroid hormones on GnRH release are reduced or absent in these species. By contrast, mating-induced preovulatory surges occasionally occur in some spontaneously ovulating species. Most research in the field of GnRH neurobiology has been performed using spontaneous ovulators including rat, guinea pig, sheep, and rhesus monkey. This review summarizes the literature concerning the neuroendocrine mechanisms controlling GnRH biosynthesis and release in females of several induced ovulating species, and whenever possible it contrasts the results with those obtained for spontaneously ovulating species. It also considers the adaptive, evolutionary benefits and disadvantages of each type of ovulatory control mechanism. In females of induced ovulating species estradiol acts in the brain to induce aspects of proceptive and receptive sexual behavior. The primary mechanism involved in the preovulatory release of GnRH among induced ovulators involves the activation of midbrain and brainstem noradrenergic neurons in response to genital-somatosensory signals generated by receipt of an intromission from a male during mating. These noradrenergic neurons project to the MBH and, when activated, promote the release of GnRH from nerve terminals in the median eminence. In contrast to spontaneous ovulators, there is little evidence that endogenous opioid peptides normally inhibit MBH GnRH release among induced ovulators. Instead, the neural signals that induce a preovulatory LH surge in these species seem to be primarily excitatory. A complete understanding of the neuroendocrine control of ovulation will only be achieved in the future by comparative studies of several animal model systems in which mating-induced as well as spontaneous, hormonally stimulated activation of GnRH neurons drives the preovulatory LH surge. KEY WORDS: GnRH; MBH; induced ovulators; neuroendocrine regulation; preovulatory LH surge; spontaneous ovulators. © 2000 Academic Press Address correspondence and reprint requests to M. J. Baum at Dept. Biology, Boston University, 5 Cummington Street, Boston...

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“…The term 'reflex' ovulator is often synonymously used with 'induced' ovulator because of the perception that ovulation occurs as a response to the stimulation of sensory nerves in the vagina and cervix by the penis during copulation (Fernandez-Baca et al 1970, Bibeau et al 1991. In contrast to the concept of a direct neural stimulus, there is increasing evidence for the presence of a biochemical substance in seminal plasma that acts in an endocrine fashion to elicit pituitary LH release and ovulation (Chen et al 1985, Pan et al 2001.…”

Section: Introductionmentioning

confidence: 99%

Evidence for the conservation of biological activity of ovulation-inducing factor in seminal plasma

Bogle¹,

Ratto²,

Adams³

2011

Reproduction

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An ovulation-inducing factor (OIF) in the seminal plasma of llamas and alpacas (induced ovulators) and cattle (spontaneous ovulators) suggests that OIF is a conserved constituent of seminal plasma among mammals. In this study, three experiments were designed to determine the biological effects of OIF in different species. In experiment 1, superstimulated prepubertal female CD-1 mice (nZ36 per group) were given a single 0.1 ml i.p. dose of 1) phosphate-buffered saline (PBS), 2) 5 mg gonadotropin-releasing hormone (GNRH), 3) 5 IU hCG, or 4) llama seminal plasma. The proportion of mice that ovulated was similar among groups treated with GNRH, hCG, or seminal plasma, and all were higher than the saline-treated group (P!0.001). In experiment 2, female llamas (nZ8 or 9 per group) were intramuscularly treated with 1) 2 ml PBS, 2) 1 ml diluted llama seminal plasma, 3) 3 ml equine seminal plasma, or 4) 3 ml porcine seminal plasma. Experiment 3 was the same as experiment 2 except that the dose of equine and porcine seminal plasma was increased to 8 and 10 ml respectively. All llamas that were treated with llama seminal plasma ovulated and none that were treated with saline ovulated (P!0.0001). The proportion of llamas that ovulated in response to equine and porcine seminal plasma was intermediate. We conclude that the mechanism for the biological response to OIF is present in prepubertal CD-1 mice and that OIF is present in equine and porcine seminal plasma.

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Vaginocervical Stimulation of Ferrets Induces Release of Luteinizing Hormone‐Releasing Hormone

Cited by 23 publications

References 24 publications

Interactions with Males Promote Rapid Changes in Gonadotropin-Releasing Hormone Immunoreactive Cells

Interactions with Males Promote Rapid Changes in Gonadotropin-Releasing Hormone Immunoreactive Cells

Neuroendocrine Regulation of GnRH Release in Induced Ovulators

Evidence for the conservation of biological activity of ovulation-inducing factor in seminal plasma

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