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Oxytocin stimulation of plasma 15-keto-13,14-dihydro prostaglandin F-2 alpha during the oestrous cycle and early pregnancy in the mare.
Abstract: In Exp. 1, 4 mares were given oxytocin intravenously (10 i.u./500 kg body wt) daily between Days 9 and 14 (Day 0 = day of ovulation) when pregnant and on Days 9-14, 16, 18, 20 when non-pregnant (not inseminated). In the non-pregnant mares the increase in plasma PGFM response to oxytocin was greater at Day 13 (235 +/- 54 pg/ml) than at Day 11 (113 +/- 38 pg/ml; P less than 0.05) and was maximum at Day 16. However, these animals did not return to oestrus and plasma progesterone did not fall below 4 ng/ml. There was no significant increase in response to oxytocin between Days 9 and 14 in the pregnant animals. In Exp. 2, when these same mares were challenged with oxytocin on alternate day (Days 9, 11 and 13 for pregnant mares, Days 9, 11, 13, 15, 17 and 19 for non-pregnant mares) there was a significant difference in the response between non-pregnant and pregnant mares by Day 13 (383 +/- 19 pg/ml vs 88 +/- 9 pg/ml; P less than 0.005). Plasma progesterone concentrations declined normally and the mares returned to oestrus. During oestrus the response to oxytocin decreased dramatically in mares receiving oxytocin on alternate days, and no response was seen by Day 19. The response also declined after Day 16 in the non-pregnant mares that had daily injections of oxytocin even though plasma progesterone remained elevated. The decreased response coincided with the increase in plasma oestrogen concentrations, suggesting that oestrogens play a role in the control of the response.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1987-01-01 PubMed ID: 3479581 The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research investigates the effect of oxytocin, a hormone that plays a significant role in pregnancy, on oestrous cycle and early pregnancy in mares. The study observes changes in plasma PGFM response, a hormonal response, linked to oxytocin administration during both pregnancy and non-pregnant stages.
Experiment Details
- Two experiments were conducted involving four mares. The focus was to analyze the effect of intravenously injected oxytocin (10 i.u./500 kg body wt) daily between specific time periods.
- In the first experiment, oxytocin was given daily to the mares between Days 9 and 14, where Day 0 is considered as the day of ovulation. This was done both when the mares were pregnant and when they were not inseminated.
- The second experiment followed a similar format, however, in this case, the mares were only given oxytocin on alternate days.
Results of the Experiments
- In non-pregnant mares, the increase in plasma PGFM response to oxytocin was more on Day 13 as compared to Day 11. The response was at its maximum on Day 16. Some hormonal changes were observed, but these did not lead the mares back to oestrus, a period of sexual receptivity in females.
- By contrast, there was no significant increase in plasma PGFM response to oxytocin between Days 9 and 14 in pregnant mares in the first experiment.
- Results of the second experiment showed that by Day 13, there was a noticeable difference in the response between non-pregnant and pregnant mares.
- Progesterone concentrations decreased normally, and the mares returned to oestrus in the second experiment. Additionally, the response to oxytocin decreased dramatically during oestrus, and by Day 19, no response was observed.
Implication of Results
- Overall, the study suggests that the hormonal changes caused by oxytocin injections were different in pregnant and non-pregnant mares. Particularly, the decrease in response coincided with an increase in oestrogen concentrations, implying that oestrogens could play a role in controlling the response to oxytocin.
Cite This Article
APA
Goff AK, Pontbriand D, Sirois J.
(1987).
Oxytocin stimulation of plasma 15-keto-13,14-dihydro prostaglandin F-2 alpha during the oestrous cycle and early pregnancy in the mare.
J Reprod Fertil Suppl, 35, 253-260.
Publication
Researcher Affiliations
- Centre de recherche en reproduction animale, Faculté de médicine vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada.
MeSH Terms
- Animals
- Dinoprost / analogs & derivatives
- Estrus / blood
- Estrus / drug effects
- Female
- Horses / blood
- Oxytocin / pharmacology
- Pregnancy
- Pregnancy, Animal / blood
- Pregnancy, Animal / drug effects
- Progesterone / blood
- Prostaglandins F / blood
Citations
This article has been cited 9 times.- Klein C, Bruce P, Hammermueller J, Hayes T, Lillie B, Betteridge K. Transcriptional profiling of equine endometrium before, during and after capsule disintegration during normal pregnancy and after oxytocin-induced luteostasis in non-pregnant mares. PLoS One 2021;16(10):e0257161.
- Swegen A. Maternal recognition of pregnancy in the mare: does it exist and why do we care?. Reproduction 2021 May 5;161(6):R139-R155.
- Gibson C, de Ruijter-Villani M, Bauersachs S, Stout TAE. Asynchronous Embryo Transfer Followed by Comparative Transcriptomic Analysis of Conceptus Membranes and Endometrium Identifies Processes Important to the Establishment of Equine Pregnancy. Int J Mol Sci 2020 Apr 7;21(7).
- Smits K, Gansemans Y, Tilleman L, Van Nieuwerburgh F, Van De Velde M, Gerits I, Ververs C, Roels K, Govaere J, Peelman L, Deforce D, Van Soom A. Maternal Recognition of Pregnancy in the Horse: Are MicroRNAs the Secret Messengers?. Int J Mol Sci 2020 Jan 9;21(2).
- Smits K, Willems S, Van Steendam K, Van De Velde M, De Lange V, Ververs C, Roels K, Govaere J, Van Nieuwerburgh F, Peelman L, Deforce D, Van Soom A. Proteins involved in embryo-maternal interaction around the signalling of maternal recognition of pregnancy in the horse. Sci Rep 2018 Mar 27;8(1):5249.
- Aurich C, Budik S. Early pregnancy in the horse revisited - does exception prove the rule?. J Anim Sci Biotechnol 2015;6:50.
- Siemieniuch-Tartanus M. The early pregnancy in mares - What do we still not know?. Vet Anim Sci 2025 Jun;28:100441.
- Ulaangerel T, Mu S, Sodyelalt J, Yi M, Zhao B, Hao A, Wen X, Han B, Bou G. Transcriptome Analysis Reveals Equine Endometrium's Gene Expression Profile Around Embryo Fixation. Genes (Basel) 2025 Feb 1;16(2).
- Bazer FW, Johnson GA. Early Embryonic Development in Agriculturally Important Species. Animals (Basel) 2024 Jun 26;14(13).
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