Developmental changes in the gonadotropin releasing hormone neuron of the female rabbit: effects of tamoxifen citrate and pregnant mare serum gonadotropin.
Abstract: Developmental changes in immunostained gonadotropin releasing hormone neurons were demonstrated in female rabbits assigned to the following treatment groups: (i) tamoxifen citrate, 10 mg.kg-1 x day-1, in sesame seed oil (vehicle) (n = 24) or (ii) vehicle alone (control, n = 24) for 108 days; and (iii) 50 IU of pregnant mare serum gonadotropin on postnatal days 22 and 25 (n = 24) or vehicle on nontreatment days. Treatments had no effect on the total number of immunostained cells, but there was a significant (p = 0.0160) developmental shift from cells with smooth processes to rough. Group comparisons revealed that there was a significant (p < 0.001) age-related increase in the number of rough cells in pregnant mare serum treated rabbits between days 25 and 75, indicating an advancement in the shift from smooth to rough cells. Plasma gonadotropin levels, ovarian follicular development, and the developmental shift from smooth to rough cells were markedly suppressed by tamoxifen treatment compared with rabbits of the control group, while no difference in estradiol levels were found. Our results suggest that a developmental shift in gonadotropin releasing hormone cell morphology from smooth to rough precedes sexual maturity in the female rabbit.
Publication Date: 1993-10-01 PubMed ID: 8143234DOI: 10.1139/y93-114Google Scholar: Lookup
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- Journal Article
Summary
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The research article is about the study of the developmental changes in gonadotropin releasing hormone (GnRH) neurons in female rabbits, and the effects of certain treatments like tamoxifen citrate and pregnant mare serum gonadotropin on these changes.
Objective of the Research
- The study aimed at understanding the developmental changes in gonadotropin releasing hormone (GnRH) neurons in female rabbits. The focus was on the effect of two specific treatments: tamoxifen citrate and pregnant mare serum gonadotropin.
Research Methodology
- Female rabbits were divided into three treatment groups. The first group was treated with tamoxifen citrate (10 mg.kg-1 x day-1) in sesame seed oil, the second group was given only the vehicle (sesame seed oil) as a control, and a third group was treated with 50 IU of pregnant mare serum gonadotropin on postnatal days 22 and 25.
- The treatments were conducted for 108 days and observations were made on their effects on the developmental changes in the GnRH neurons of the rabbits.
Findings of the Study
- The treatments had no effect on the total number of immunostained cells, but there was a significant developmental shift in cell morphology from smooth to rough.
- The pregnant mare serum gonadotropin treatment induced a significant age-related increase in the number of rough cells between days 25 and 75, indicating an advancement in the shift from smooth to rough cells.
- The tamoxifen treatment resulted in a significant suppression of plasma gonadotropin levels, ovarian follicular development, and the developmental shift from smooth to rough cells compared to the control group.
Conclusion
- The study found that a developmental shift in GnRH cell morphology from smooth to rough precedes the sexual maturity in the female rabbit.
- The results of the study can help in further understanding of the reproductive cycle in female animals and implications of different hormonal treatments on it.
Cite This Article
APA
Foster WG, Jarrell JF, YoungLai EV.
(1993).
Developmental changes in the gonadotropin releasing hormone neuron of the female rabbit: effects of tamoxifen citrate and pregnant mare serum gonadotropin.
Can J Physiol Pharmacol, 71(10-11), 761-767.
https://doi.org/10.1139/y93-114 Publication
Researcher Affiliations
- Department of Obstetrics and Gynecology, McMaster University Medical Centre, Hamilton, ON, Canada.
MeSH Terms
- Animals
- Body Weight / drug effects
- Brain / cytology
- Brain / drug effects
- Brain / growth & development
- Estradiol / blood
- Estradiol / pharmacology
- Female
- Follicle Stimulating Hormone / blood
- Gonadotropin-Releasing Hormone / physiology
- Gonadotropins, Equine / pharmacology
- Luteinizing Hormone / blood
- Neurons / physiology
- Organ Size / drug effects
- Ovarian Follicle / anatomy & histology
- Ovarian Follicle / drug effects
- Ovarian Follicle / physiology
- Rabbits
- Radioimmunoassay
- Receptors, Estradiol / drug effects
- Sexual Behavior, Animal / drug effects
- Sexual Behavior, Animal / physiology
- Sexual Maturation / drug effects
- Tamoxifen / pharmacology
Citations
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