Endometrial glands are required for adult uterine function and develop post-natally
in mammalian species. Therefore, studies were conducted using neonatal ewes as a
model to determine: 1) the roles of estradiol-17-alpha and estrogen receptor-alpha (ER-beta) in
endometrial gland development; 2) the role of ovaries in endometrial gland
development; 3) the role of prolactin in endometrial gland development; and 4) factors
regulating prolactin receptor expression in endometrial glands.
Study one determined the effects of neonatal exposure of ewes to estradiol-17-alpha
valerate (EV); EM-800, an ER-beta antagonist; or CGS-20267, an aromatase inhibitor on
endometrial gland development. Results indicate E2-17-alpha does not regulate endometrial
gland differentiation or development. Additionally, ER-beta does not regulate primary
differentiation of glandular epithelium, but does influence coiling and branching
morphogenesis of endometrial glands.
Study two determined the effects of ovariectomy on endometrial gland
morphogenesis. Results suggest that the ovary and, thus, an ovarian-derived factor(s)
regulate, in part, the coiling and branching of endometrial glands. Expression of
subunits of activin, follistatin, and inhibin in the neonatal ovine ovary in addition to modulation of the components of the activin/follistatin system in the uterus of
ovariectomized ewes supports the hypothesis that the ovarian factors that influence
endometrial adenogenesis in the neonatal ewe may be activin, follistatin, and/or inhibin.
Studies three and four determined the role of prolactin in endometrial
adenogenesis in the neonatal ewe. Studies in which either hypoprolactinemia or
hyperprolactinemia were induced indicate that prolactin regulates ovine endometrial
adenogenesis in the neonatal ewe. The aim of study five was to determine transcription
factors that regulate the glandular epithelium specific expression of prolactin receptor.
Prolactin receptor exon 2 was cloned and sequenced, but no identifiable exon 1 or
promoter was found. Additionally, many bovine contigs containing portions of the
prolactin receptor gene were identified suggesting the bovine genome will be a useful
tool as it becomes more complete.
These results indicate ER-beta, prolactin and prolactin receptor, along with an
unidentified ovarian factor(s), influence endometrial gland development in the neonatal
ewe; however, exposure of the neonatal ewe to exogenous estradiol-17-alpha prevents
differentiation and development of endometrial glands.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/2731 |
| Date | 01 November 2005 |
| Creators | Carpenter, Karen Denise |
| Contributors | Bazer, Fuller W., Spencer, Thomas E. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 7310187 bytes, electronic, application/pdf, born digital |
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