Concentrations of altrenogest in plasma of mares and foals and in allantoic and amniotic fluid at parturition.
Abstract: Treatment with the progestin altrenogest is widely used in pregnant mares. The fact that foals born from healthy mares treated with altrenogest until term suffered from neonatal problems raises the question of direct effects of altrenogest on vital functions in the neonate. We have therefore investigated altrenogest concentrations in maternal and neonatal blood plasma and in fetal fluids. Pregnant mares were treated with altrenogest orally once daily (0,088 mg/kg bodyweight, n = 7) or left untreated (n = 8) from 280 d of gestation until foaling. Altrenogest concentration was determined in plasma of the mares, their foals and in amniotic and allantoic fluid. The concentration of altrenogest in plasma from treated mares (2.6 +/- 1.0 ng/mL) was significantly lower than in plasma from their foals immediately after birth (5.6 +/- 1.9 ng/mL; p < 0.05), but was significantly higher than in their fetal fluids (amniotic fluid: 0.4 +/- 0.1 ng/mL; p < 0.05; allantoic fluid: 3.0 +/- 1.5 ng/mL). Altrenogest was undetectable in maternal and fetal plasma and fetal fluids of control pregnancies at all times. Altrenogest concentration in plasma of foals from treated mares was strongly correlated to the altrenogest concentration in plasma of their dams (r = 0.938, p < 0.001) and in amniotic (r = 0.886, p < 0.001) and allantoic fluid (r = 0.562, p < 0.05). A significant decrease in altrenogest concentration between the time periods 0-15 min, 30-120 min, and 180-360 min after parturition was seen in the plasma from foals born to altrenogest-treated mares. In conclusion, our data demonstrate that altrenogest reaches the equine fetus at high concentrations.
Copyright 2010 Elsevier Inc. All rights reserved.
Publication Date: 2010-05-10 PubMed ID: 20452000DOI: 10.1016/j.theriogenology.2010.02.006Google Scholar: Lookup
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Summary
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This research explores the effects of altrenogest—a type of progestin, on pregnant horses and their foals. The study demonstrated that altrenogest can reach the equine fetus in significant concentrations, and that the levels of the drug in the foals’ plasma at birth are higher than in the mothers’ plasma.
Research Purpose and Methodology
- The research was conducted to understand potential direct effects of altrenogest on vital functions in newborn horses, known as foals.
- Altrenogest is widely used in pregnant mares (female horses), but there have been instances of neonatal complications in foals born from mares treated with this drug.
- The researchers investigated altrenogest levels in the blood plasma of mares and neonates, as well as in amniotic and allantoic fluid, which were both fetal fluids.
- Two groups of mares were used for this research: a control group that received no treatment (n=8) and a test group that was given altrenogest orally once daily (0.088 mg/kg body weight, n=7) from the 280th day of gestation until foaling.
Findings of the Research
- Altrenogest concentration in the blood of treated mares was found to be significantly lower than that in the blood of their foals at birth.
- However, the concentration of altrenogest in the mare’s plasma was significantly higher than in the fetal fluids of the same mare.
- Untreated mares and their foals, as well as the fetal fluids of these untreated pregnancies, exhibited no detectable altrenogest at any stage.
- Altrenogest concentration in the plasma of newborn foals delivered by treated mares correlates significantly with the altrenogest concentration in the plasma of their mothers and in the amniotic and allantoic fluids.
- A significant decrease was seen in the altrenogest concentration in foal plasma over different time periods (0-15 min, 30-120 min, and 180-360 min) after birth in foals born to altrenogest-treated mares.
Concluding Observations
- The data from this study confirms that altrenogest is transmitted in high concentrations to the equine fetus. This finding indicates that altrenogest treatment in pregnant mares impacts not only the mothers but may also have direct neonatal effects on the foals.
Cite This Article
APA
Palm FM, Schenk I, Neuhauser S, Schubert D, Machnik M, Schänzer W, Aurich C.
(2010).
Concentrations of altrenogest in plasma of mares and foals and in allantoic and amniotic fluid at parturition.
Theriogenology, 74(2), 229-235.
https://doi.org/10.1016/j.theriogenology.2010.02.006 Publication
Researcher Affiliations
- Clinic for Obstetrics, Gynecology and Andrology, University for Veterinary Sciences, Vienna, Austria.
MeSH Terms
- Allantois / metabolism
- Amniotic Fluid / metabolism
- Animals
- Animals, Newborn / blood
- Female
- Horses / blood
- Horses / metabolism
- Maternal-Fetal Exchange
- Parturition / metabolism
- Pregnancy
- Pregnancy Complications / drug therapy
- Progesterone Congeners / adverse effects
- Progesterone Congeners / blood
- Progesterone Congeners / metabolism
- Progesterone Congeners / therapeutic use
- Trenbolone Acetate / adverse effects
- Trenbolone Acetate / analogs & derivatives
- Trenbolone Acetate / blood
- Trenbolone Acetate / metabolism
- Trenbolone Acetate / therapeutic use
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