Comparison of the effects of two GnRH antagonists on LH and FSH secretion, 
follicular growth and ovulation in the mare

Guillaume, Daniel; Bruneau, Bernard; Briant, Christine

doi:10.1051/rnd:2002023

Cited by 16 publications

(11 citation statements)

References 26 publications

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“…Plasma LH concentration was assayed by RIA following a procedure adapted from Guillaume et al [26]. All samples were run in duplicate.…”

Section: Hormone Assaysmentioning

confidence: 99%

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Acute Injection and Chronic Perfusion of Kisspeptin Elicit Gonadotropins Release but Fail to Trigger Ovulation in the Mare1

Decourt¹,

Caraty²,

Briant³

et al. 2014

Biology of Reproduction

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Kisspeptin has emerged as the most potent gonadotropin-releasing hormone (GnRH) secretagogue and appears to represent the penultimate step in the central control of reproduction. In the sheep, we showed that kisspeptin could be used to manipulate gonadotropin secretion and control ovulation. Prompted by these results, we decided to investigate whether kisspeptin could be used as an ovulation-inducing agent in another photoperiodic domestic mammal, the horse. Equine kisspeptin-10 (eKp10) was administered intravenously as bolus injections or short- to long-term perfusions to Welsh pony mares, either during the anestrus season or at various stages of the cycle during the breeding season. In all the experimental conditions, eKp10 reliably increased peripheral concentrations of both luteinizing hormone and follicle-stimulating hormone. The nature of the response to eKp10 was consistent across experimental conditions and physiological states: the increase in gonadotropins was always rapid and essentially transient even when eKp10 was perfused for prolonged periods. Furthermore, eKp10 consistently failed to induce ovulation in the mare. To gain insights into the underlying mechanisms, we used acute injections or perfusions of GnRH. We also cloned the equine orthologues of the kisspeptin precursor and Kiss1r; this was justified by the facts that the current equine genome assembly predicted an amino acid difference between eKp10 and Kp10 in other species while an equine orthologue for Kiss1r was missing altogether. In light of these findings, potential reasons for the divergence in the response to kisspeptin between ewe and mare are discussed. Our data highlight that kisspeptin is not a universal ovulation-inducing agent.

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“…Plasma LH concentration was assayed by RIA following a procedure adapted from Guillaume et al [26]. All samples were run in duplicate.…”

Section: Hormone Assaysmentioning

confidence: 99%

“…Plasma progesterone concentration was determined using a previously validated procedure [26]. The detection limit was 125 pg/ml.…”

Section: Hormone Assaysmentioning

confidence: 99%

Acute Injection and Chronic Perfusion of Kisspeptin Elicit Gonadotropins Release but Fail to Trigger Ovulation in the Mare1

Decourt¹,

Caraty²,

Briant³

et al. 2014

Biology of Reproduction

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“…Determinations of eFSH in blood plasma samples and in fractions during the different purification steps of the eFSH preparation, together with eLH and progesterone in plasma samples were carried out using specific 125 IRIAs (Guillaume et al 2002). All samples were run in duplicate.…”

Section: Hormone Assaysmentioning

confidence: 99%

“…Additionally, to depress endogenous gonadotrophin secretion, vaginal sponges impregnated with progestagen (500 mg Altrenogest/sponge, Regumate, Hoechst Roussel Vet, SA, Pantin, France) and oestrogen (50 mg beta-oestradiol-3 benzoate/sponge, Sigma E8515) (Driancourt & Palmer 1982) were inserted in the vagina from the day before the eFSH injection until the last blood sample. The mares were also injected with a gonadotrophin releasing hormone (GnRH) antagonist (antarelix, Teverelix, Europeptides, Argenteuil, France, 0·01 mg/kg, i.v., twice a day at 0700 h and 1900 h) (Guillaume et al 2002) from two days before the injection of eFSH until the last blood sample. All four mares received each of four doses of eFSH (4·4, 8·8, 17·6 and 35·2 µg/kg) at one-week intervals in a randomized 4 4 Latin Square protocol.…”

Section: Kinetic Studiesmentioning

confidence: 99%

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Kinetic studies and production rate of equine (e) FSH in ovariectomized pony mares. Application to the determination of a dosage regimen for eFSH in a superovulation treatment

Briant

Toutain²,

Ottogalli³

et al. 2004

Journal of Endocrinology

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The appropriate dosage regimen for equine FSH (eFSH) (dose, dosing interval) administration in a superovulation treatment in pony mares was determined by a kinetic approach using production rates and kinetic parameters of elimination of the hormone. Two dosage regimens were then tested in superovulation protocols. The eFSH production rates were determined by sampling four ovariectomized pony mares every 10 min for 8 h during the breeding season. Kinetic parameters were determined by administering four dose levels of a preparation of eFSH (4·4, 8·8, 17·6 and 35·2 µg/kg) by the i.v. route to the same mares, in a randomized 4 4 Latin Square protocol. The overall mean plasma clearance was 0·256 0·07 ml.kg 1 .min 1 , and was independent of the dose. The mean residence time ranged from 5·5 to 10·8 h and increased with the dose. The estimated FSH production rates were 8·6 to 15·3 µg.kg 1 .day 1 (i.e. 2·89 to 3·45 mg per day per mare). Two dosage regimens of eFSH were then tested in cyclic mares (ten treated mares in each trial): 3·45 mg per day (4·4 µg/kg three times a day by the i.v. route), which corresponds to the maximal daily production rate of the native hormone in ovariectomized mares, and 1·72 mg per day (2·2 µg/kg three times a day), which corresponds to half of that production rate. The dosage regimen of 2·2 µg/kg three times a day gave satisfactory results in terms of efficacy (numbers of ovulations and embryos) with minimal unwanted effects (luteinized or anovulatory follicles).

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Functional relationships among intrafollicular insulin-like growth factor 1, circulatory gonadotropins, and development of the dominant follicle in mares

Checura

Beg

Parrish

et al. 2010

Animal Reproduction Science

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Comparison of the effects of two GnRH antagonists on LH and FSH secretion, follicular growth and ovulation in the mare

Cited by 16 publications

References 26 publications

Acute Injection and Chronic Perfusion of Kisspeptin Elicit Gonadotropins Release but Fail to Trigger Ovulation in the Mare1

Acute Injection and Chronic Perfusion of Kisspeptin Elicit Gonadotropins Release but Fail to Trigger Ovulation in the Mare1

Kinetic studies and production rate of equine (e) FSH in ovariectomized pony mares. Application to the determination of a dosage regimen for eFSH in a superovulation treatment

Functional relationships among intrafollicular insulin-like growth factor 1, circulatory gonadotropins, and development of the dominant follicle in mares

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