Changes in PGF2alpha secretion during prolonged luteal phase in mares.
Abstract: The aim of this study was to characterize changes in PGF2alpha secretion in mares with persistent corpora lutea that were induced by administering altrenogest during oestrus. In Expt 1, PGF2alpha secretion was compared among mares undergoing normal oestrous cycles (n=7) and mares undergoing prolonged luteal phases (n=6), using the mean 15-ketodihydro-PGF2alpha (PGFM) plasma concentrations, peak PGFM concentrations and number of PGFM surges each day, from day 12 to day 16 of the luteal phase. In Expt 2, oxytocin-induced PGF2alpha secretion was characterized on days 13 and 16 of the luteal phase in mares undergoing normal oestrous cycles (n=6) and in mares undergoing prolonged luteal phases (n=7) by comparing the oxytocin-induced increase in PGFM concentration and total PGF2alpha secretion. In Expt 1, mean PGFM concentrations, peak PGFM concentrations and number of PGFM surges per day were significantly lower in mares undergoing prolonged luteal phases than in mares undergoing normal luteal phases. In Expt 2, the area under the curve for PGFM ng (90 min)(-1) was similar for both groups on day 13 but was significantly lower on day 16 in mares undergoing prolonged luteal phases than in mares undergoing normal luteal phases. No change in total PGF2alpha secretion was observed between day 13 and 16 for mares undergoing normal luteal phases, but a significant decrease was observed from day 13 to day 16 in mares undergoing prolonged luteal phases. On days 13 and 16, the increase in PGFM concentration 5 min after oxytocin administration was significantly higher in mares undergoing normal luteal phases than in mares undergoing prolonged luteal phases. The increase in PGFM concentration 5 min after oxytocin administration was similar on days 13 and 16 for mares undergoing normal luteal phases, but tended to be less on day 16 in mares undergoing prolonged luteal phases. These results indicate that failure of luteolysis in mares undergoing induced prolonged luteal phases is due to decreased uterine sensitivity to oxytocin stimulation or decreased uterine ability to secrete prostaglandin.
Publication Date: 2000-01-01 PubMed ID: 20681142
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research study investigates changes in PGF2alpha secretion in mares during prolonged periods of the luteal phase, and how that may affect uterine sensitivity to oxytocin or ability to secrete prostaglandin.
Research Method
- The study focuses on two experiments, with both involving comparisons between mares undergoing regular oestrous cycles and those experiencing prolonged luteal phases that were induced by administering altrenogest during oestrus.
Results of Experiment 1
- Experiment 1 examines PGF2alpha secretion in both groups from day 12 to day 16 of the luteal phase, using metrics such as mean 15-ketodihydro-PGF2alpha (PGFM) plasma concentrations, peak PGFM concentrations, and number of PGFM surges each day.
- The mares with prolonged luteal phases demonstrated significantly lower mean PGFM concentrations, peak PGFM concentrations, and number of daily PGFM surges compared to those undergoing normal oestrous cycles.
Results of Experiment 2
- Experiment 2 looks at oxytocin-induced PGF2alpha secretion on the 13th and 16th days of the luteal phase in both groups, comparing the oxytocin-induced increase in PGFM concentration and total PGF2alpha secretion.
- On day 16, mares with prolonged luteal phases had a significantly lower area under the curve for PGFM ng (90 min)(-1) compared to those undergoing normal luteal phases. There was no significant difference on day 13.
- The total PGF2alpha secretion did not change between day 13 and 16 for mares undergoing normal luteal phases, but there was a notable decrease in the prolonged luteal phase group.
- The increase in PGFM concentration 5 min after oxytocin administration was significantly higher in mares undergoing normal luteal phases than in those with prolonged luteal phases. Moreover, in the prolonged luteal phase group, this increase tended to lessen on day 16.
Conclusion
- The results indicate that failure of luteolysis in mares undergoing prolonged luteal phases is presumably due to a decreased uterine sensitivity to oxytocin stimulation or a reduced ability of the uterus to secrete prostaglandin.
Cite This Article
APA
Kindahl H, Odensvik K, Hansen B, Daels PF.
(2000).
Changes in PGF2alpha secretion during prolonged luteal phase in mares.
J Reprod Fertil Suppl(56), 305-315.
Publication
Researcher Affiliations
- Department of Obstetrics and Gynaecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
MeSH Terms
- Animals
- Dinoprost / genetics
- Dinoprost / metabolism
- Estrous Cycle / physiology
- Female
- Horses / metabolism
- Luteal Phase / drug effects
- Luteal Phase / physiology
- Progestins / pharmacology
- Trenbolone Acetate / analogs & derivatives
- Trenbolone Acetate / pharmacology
Citations
This article has been cited 1 times.- Hedberg Y, Dalin AM, Santesson M, Kindahl H. A preliminary study on the induction of dioestrous ovulation in the mare--a possible method for inducing prolonged luteal phase. Acta Vet Scand 2006 Jul 26;48(1):12.
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