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Studies of oestrogen and progesterone receptors in the sow uterus

with special emphasis on the oestrous cycle and early pregnancy

Sukjumlong, Sayamon (2005). Studies of oestrogen and progesterone receptors in the sow uterus. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2005:35
ISBN 91-576-7034-x
[Doctoral thesis]

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Abstract

Ovarian steroid hormones and their respective receptors are essential for normal reproductive physiology. The aim of the present thesis was to investigate immunolocalization of oestrogen (ER) and progesterone (PR) receptors and levels of their mRNAs as well as proliferative activities (Ki-67 protein) in the sow uterus during the oestrous cycle and at early pregnancy. Fifteen non-pregnant cyclic sows and eighteen inseminated/early pregnant sows were used. The cyclic sows were slaughtered at different stages of the oestrous cycle (prooestrus; oestrus; early dieostrus; dioestrus and late dioestrus). The inseminated sows were slaughtered at 5-6 h after AI, 20-25 h and 70 h after ovulation, d 11 and d 19 after the start of standing oestrus. After slaughter, uterine samples were fixed in 10% formaldehyde, embedded in paraffin and sectioned. Immunohistochemistry was used to investigate the localization of ERα, PR and Ki-67. The uterine tissues were studied according to different compartments; surface epithelium (SE), glandular epithelium (GE, superficial and deep layer), subepithelial connective tissue (CNT) and myometrium (MYO). The evaluation was done by manual scoring of intensity (ERα in all compartments except connective tissue), cell counting (ERα in connective tissue and Ki-67 cells) and image analysis (PR). Frozen tissue samples were subject to solution hybridization, measuring the levels of mRNAs for ERα, ER and PR in the endometrium and myometrium. The immunolocalization of steroid receptor proteins and proliferating cells was exclusively found in the nuclei of uterine cells, except for cytoplasmic ERα staining in the SE at early dioestrus/70 h after ovulation. The staining patterns varied with stage of the oestrous cycle/pregnancy as well as with uterine tissue compartment. In the SE, the most prominent staining for ERα was found at early dioestrus, suggesting a delayed effect from high levels of oestradiol-17β at oestrus while insemination was related to lower levels already at 20-25 h after ovulation. For PR in the SE, there was no obvious difference between cyclic and inseminated/early pregnant sows. In the deep GE, high presence of ERα at early dioestrus/70 h after ovulation may be related to the high proliferation found at that stage. A positive correlation was found between oestradiol-17β and PR in the GE while the correlation with progesterone was negative as represented by the lower levels of glandular PR at dioestrus/early pregnancy being downregulated by high levels of progesterone. In the CNT, both ERα and PR were high when oestrogen was high and lower when progesterone levels increased. PR levels were relatively more uniform than in other tissues, indicating a role in mediating hormonal influence when the receptor levels are low in those tissues. A mediating role by the CNT is also suggested by the significant correlation found between numbers of ERα cells in the CNT and Ki-67 cells in the epithelia of both cyclic (SE and GE) and inseminated sows (SE), whereby oestrogens indirectly may stimulate proliferation. In the MYO, ERα and PR showed the same pattern of localization with high presence around oestrus for both experiments. ERα is suggested to mediate myometrial activity whereas PR may be needed for myometrial quiescence after ovulation. In the endometrium, similar variations in ERα mRNA and PR mRNA levels were found, indicating common regulatory mechanisms. The expression of ERβ mRNA in both endometrium and myometrium was consistently low in cyclic sows, but higher after insemination implying that ERβ is less necessary for reproductive processes during the oestrous cycle but is more important during pregnancy. Also lower ratios of mRNA for ERα/ERβ in inseminated compared to cyclic sows, indicate a more important role for ERβ in pregnant sows. A higher ratio of mRNA for ERα/ERβ found at early dioestrus/70 h after ovulation may represent a potentially higher sensitivity to oestrogen at these stages which in turn may be related to the high proliferation found in the uterine epithelia.

Authors/Creators:Sukjumlong, Sayamon
Title:Studies of oestrogen and progesterone receptors in the sow uterus
Subtitle:with special emphasis on the oestrous cycle and early pregnancy
Year of publishing :April 2005
Volume:2005:35
Number of Pages:48
Papers/manuscripts:
NumberReferences
ALLI. Sukjumlong, S., Kaeoket, K., Dalin, A.-M. & Persson, E. 2003. Immunohistochemical studies on oestrogen receptor alpha (ERα) and the proliferative marker Ki-67 in the sow uterus at different stages of the oestrous cycle. Reproduction in Domestic Animals 38, 5-12. II. Sukjumlong, S., Persson, E., Kaeoket, K. & Dalin, A.-M. 2004. Immunohistochemical Studies on Oestrogen Receptor Alpha (ERα) and the Proliferative Marker Ki-67 in the Sow Uterus at Oestrus and Early Pregnancy. Reproduction in Domestic Animals 39, 361-369. III. Sukjumlong, S., Dalin, A.-M., Sahlin, L. & Persson, E. 2005. Immunohistochemical studies on the progesterone receptor (PR) in the sow uterus during the oestrous cycle and in inseminated sows at oestrus and early pregnancy. Reproduction 129, 349-359. IV. Sukjumlong, S., Persson, E., Dalin, A.-M., Janson, V. & Sahlin, L. Comparative studies of mRNAs for oestrogen receptors α and β and progesterone receptors in the sow uterus during the oestrous cycle and in inseminated sows at oestrus and early pregnancy. Submitted for publication.
Place of Publication:Uppsala
ISBN for printed version:91-576-7034-x
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L53 Animal physiology - Reproduction
Subjects:Not in use, please see Agris categories
Agrovoc terms:sows, uterus, oestrous cycle, oestrogens, progestogenes, artificial insemination, pregnancy
Keywords:Sow-uterus, Oestrogen receptor alpha (ERα), Oestrogen receptor beta (ERβ), Progesterone receptors (PR), Oestrous cycle, Insemination, Pregnancy
URN:NBN:urn:nbn:se:slu:epsilon-599
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-599
ID Code:581
Department:(VH) > Dept. of Anatomy, Physiology and Biochemistry
Deposited By: Sayamon Sukjumlong
Deposited On:07 Apr 2005 00:00
Metadata Last Modified:02 Dec 2014 10:05

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