Concentrations of altrenogest in plasma of mares and foals and in allantoic and amniotic fluid at parturition

Palm, Franziska; Schenk, Ina; Neuhauser, Stefanie; Schubert, Daniel; Machnik, Marc; Schänzer, Wilhelm; Aurich, Christine

doi:10.1016/j.theriogenology.2010.02.006

Cited by 14 publications

(14 citation statements)

References 26 publications

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“…Results showed that no significant differences were observed on T max , C max , T 1/2λz , V ss , and AUC last (Table 1). Most of altrenogest was eliminated within 24 hr with a very low trough concentration before the next dosing, similar to the horse study, which did not affect subsequent dosing (Lampinensalomonsson, Beckman, Bondesson, & Hedeland, 2006;Machnik et al, 2007;Palm et al, 2010). This could be due to the rapid elimination rate of altrenogest.…”

Section: Discussionsupporting

confidence: 62%

Pharmacokinetics of altrenogest in gilts

Xiao

Sun

et al. 2019

Vet Pharm & Therapeutics

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Altrenogest, a synthetic progestogen, is characterized by its estrus synchronization in mares, ewes, sows, and gilts. To investigate the pharmacokinetic profile and evaluate its accumulation in gilts, 18 oral doses of 20 mg altrenogest/gilt/day were given to eight healthy gilts at an interval of 24 hr. Plasma samples were collected, and altrenogest was determined by ultra‐high‐performance liquid chromatography with mass spectrometry. WinNonlin 6.4 software was used to calculate the pharmacokinetic parameters through noncompartmental model analysis. After the first administration (D 1), the pharmacokinetic parameters, including Tmax, Cmax, and the elimination half‐life (T1/2λz), were similar to those observed after the final administration (D 18). However, the mean residence time at D 1 was significantly lower than D 18. As a whole, the mean steady‐state plasma concentration (Css), degree fluctuation (DF), accumulation factor (Rac), and area under the plasma concentration–time curve in steady state (AUCss) were 22.69 ± 6.15 ng/ml, 270.64 ± 42.51%, 1.53 ± 0.23, and 544.63 ± 147.49 ng hr/ml, respectively. These results showed that after 18 consecutive days of oral administration of altrenogest, plasma concentrations of altrenogest had a certain degree of fluctuation, without significant accumulations.

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Section: Discussionsupporting

confidence: 62%

Pharmacokinetics of altrenogest in gilts

Xiao

Sun

et al. 2019

Vet Pharm & Therapeutics

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“…Altrenogest has become a standard treatment for mares, but it does cross the placenta and foals are exposed to it [96]. The earliest studies on altrenogest given to pregnant mares yielded definitive evidence of potential adverse effects in the foals which, in the case of fillies, demonstrated how the drug was androgenic and progestogenic.…”

Section: The Luteo-placental Shiftmentioning

confidence: 99%

Review of the reproductive endocrinology of the pregnant and parturient mare

Conley

2016

Theriogenology

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“…Although placental efficiency may be to some extent higher in pony breeds [22], progestin synthesis and release appear to depend more on placental size. Compared to mares, progestin concentration was elevated in foals between 30 and 60 min after birth but has been reported previously to decrease markedly during the first hours of life [26].…”

Section: Discussionmentioning

confidence: 54%

Differences in Endocrine and Cardiac Changes in Mares and Her Fetus before, during, and after Parturition in Horses of Different Size

Nagel¹,

Melchert

Aurich

et al. 2020

Animals

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Equine fetomaternal monitoring is based on endocrine and cardiac parameters which may differ among small, medium-size, and full-size horses. Therefore, Shetland (n = 6), Haflinger (n = 8), and Warmblood pregnancies (n = 9) were studied during late gestation and at foaling. Weight of mares, foals and placenta, plasma progestin and cortisol concentration, heart rate and heart rate variability (HRV) were determined. Foal weight always approximated 10% of mare weight but relative placenta weight was highest in full-size mares (p < 0.05). Progestin (p < 0.001) and cortisol (p < 0.05) concentration was highest in full-size mares. Progestin concentration decreased towards parturition (p < 0.001) while cortisol concentration increased (p < 0.01). Maternal heart rate increased before foaling with the most pronounced increase in small mares (p < 0.001). The HRV increased during foaling and decreased when delivery was completed (p < 0.001). Changes were most pronounced in full-size mares (p < 0.001). Atrio-ventricular blocks regularly occurred in parturient full-size mares but only occasionally in medium-size and small mares (time p < 0.05, time × group p < 0.05). This may reflect breed differences in cardiovascular efficiency. Fetal heart rate decreased towards birth (p < 0.001) with the most pronounced decrease in full-size horses (p < 0.01). Fetal HRV showed no consistent changes before birth but increased when the foal was born (p < 0.001), this increase being most pronounced in full-size foals (p < 0.05). In conclusion, this study demonstrates both similarities and differences in peripartum endocrine and cardiac changes in horses of different size.

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Concentrations of altrenogest in plasma of mares and foals and in allantoic and amniotic fluid at parturition

Cited by 14 publications

References 26 publications

Pharmacokinetics of altrenogest in gilts

Pharmacokinetics of altrenogest in gilts

Review of the reproductive endocrinology of the pregnant and parturient mare

Differences in Endocrine and Cardiac Changes in Mares and Her Fetus before, during, and after Parturition in Horses of Different Size

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