Differential suppression of endometrial prostaglandin F2alpha by the equine conceptus.
Abstract: Prostaglandin F2alpha secretion by the uterine endometrium between Days 13 and 14 postovulation causes luteal regression in mares. A mechanism involving interruption or suppression of this secretion causes pregnancy to be maintained. The present study was designed to determine the age of the conceptus when maximal suppression of PGF2alpha secretion occurs. Mares were examined daily during estrus with ultrasonography (day 0 = day of ovulation). Conceptus tissues were recovered nonsurgically on Days 9 (n = 7), 12 (n = 5), 13 (n = 5), and 16 (n = 7) and uterine biopsies on Day 14. Both uterine and conceptus tissues were washed in phosphate-buffered saline (PBS) with 100 units penicillin G/ml + 100 microg streptomycin/ml, pH 7.4. Endometrial tissue (approximately 200 mg) plus conceptus tissues were incubated in 15 ml of tissue culture medium 199 (M199) + 10% fetal calf serum and 10 units penicillin G/ml and 10 microg streptomycin/ml at 37 degrees C under 5% CO(2): 5% O(2) : 90% N(2). Samples were taken at 4, 8, and 24 h. Two plates that contained only endometrial tissue and two additional plates with 25 mg flunixin meglumine added along with endometrial tissue were also included in the incubations. Concentrations of PGF2alpha were measured in all samples using radioimmunoassay. There was a trend toward suppression of PGF2alpha secretion by conceptus tissues, regardless of age. However, Day 12 concepti significantly suppressed PGF2alpha secretion compared with that of endometrial tissue incubated alone (P = 0.03).
Publication Date: 1996-02-01 PubMed ID: 16727817DOI: 10.1016/0093-691x(95)00401-sGoogle Scholar: Lookup
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- Journal Article
Summary
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The research looked at how the embryo of a horse (the equine conceptus) suppresses the secretion of Prostaglandin F2alpha (PGF2alpha) in the uterus (endometrum) in the early stages of pregnancy. This suppression prevents luteal regression, thereby maintaining pregnancy. The study found that this suppression is most significant around the 12th day after ovulation.
Study Methodology
- The researchers monitored mares throughout their estrus, with the day of ovulation regarded as Day 0.
- Conceptus tissues were non-surgically obtained on the 9th, 12th, 13th, and 16th days post-ovulation and uterine biopsies were taken on the 14th day.
- Both uterine and conceptus tissues were cleaned with a phosphate-buffered saline solution containing penicillin and streptomycin.
- The tissues were then incubated in a medium designed to mimic the natural environment in the mare’s body.
- Two plates of endometrial tissues were used as controls with one of them having the addition of flunixin meglumine, a pain reliever and anti-inflammatory drug.
- Samples were taken at 4, 8 and 24 hour intervals and concentrations of PGF2alpha were measured using a method called Radioimmunoassay – a technique used to measure concentrations of antigens.
Outcomes and Significance
- The results showed a pattern of PGF2alpha suppression by the equine conceptus, irrespective of its age.
- However, the suppression of PGF2alpha was notably more significant on Day 12 after ovulation compared to the secretion of PGF2alpha in endometrial tissue incubated alone.
- The finding suggests that around the 12th day post-ovulation, the equine conceptus most effectively inhibits the secretion of substances that would normally lead to luteal regression, thereby contributing to the maintenance of pregnancy.
Cite This Article
APA
Sissener TR, Squires EL, Clay CM.
(1996).
Differential suppression of endometrial prostaglandin F2alpha by the equine conceptus.
Theriogenology, 45(3), 541-546.
https://doi.org/10.1016/0093-691x(95)00401-s Publication
Researcher Affiliations
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO 80523, USA.
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