Plasma androstenedione after injections of dexamethasone and luteinizing hormone releasing hormone in young post-pubertal bulls

Chantaraprateep, P.; Thibier, M.

doi:10.1016/0378-4320(81)90014-2

Cited by 2 publications

(1 citation statement)

References 17 publications

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“…Both LH and FSH reached their maximum values later when dex¬ amethasone was injected before GnRH. The LH response was shown to be related to the depressive effect of dexamethasone on pituitary sensitivity to release this gonadotrophin (Chantaraprateep & Thibier, 1978;Thibier, 1978). To our knowledge, this has not been documented for FSH.…”

Section: Discussionmentioning

confidence: 96%

Individual variations in FSH release after a GnRH challenge and relationship with semen output in young bulls

Malak¹,

Thibier²

1985

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Blood samples collected from 54 Montbéliarde young post-pubertal bulls were assayed for FSH. In the first trial, 0.25 mg GnRH was given to each of 25 bulls at 12 months of age. In a second group of 29 bulls, each received 20 mg dexamethasone followed by 0.25 mg GnRH 5 h later. Based on measurements of semen output, the bulls were classified into three categories: good, medium and poor semen producers. The total FSH response was significantly different among individuals (P less than 0.05) and repeatable (r = 0.45) only after the combined treatment. The mean total responses did not differ significantly between the 3 categories of semen producers, but individual FSH responses were significantly and negatively correlated to quantitative and qualitative semen production characteristics (r = 0.4-0.7). It was concluded that measurement of FSH after a combined dexamethasone-GnRH challenge permits the demonstration of a significant relationship between FSH release and semen production in individual bulls.

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Section: Discussionmentioning

confidence: 96%

Individual variations in FSH release after a GnRH challenge and relationship with semen output in young bulls

Malak¹,

Thibier²

1985

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Androstendion, Epitestosteron, Testosteron und Luteinisierungshormon im Blutplasma von Stieren vor und nach Verabreichung von Gn‐RH (Lutal®)³

Möstl¹,

Choi²,

Kruip

et al. 1983

Zentralblatt für Veterinärmedizin Reihe A

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Zusammenfassung Bei neun Fleckviehstieren im Alter von acht bis zwölf Monaten wurden über einen Zeitraum von sechs Stunden Blutproben entnommen und die Konzentration von LH, Testosteron, Androstendion und Epitestosteron mittels Radioimmunoassay gemessen. Am nächsten Tag wurde den Stieren je 100μg Gn‐RH (Lutal®) intramuskulär verabreicht und wiederum die Konzentration der angeführten Hormone bestimmt. Während der sechs Stunden variierten die Hormonkonzentrationen im Blut der Stiere zwischen 3,3 und 1,72ng/ml für LH, 4,2 und 1,0ng/ml für Testosteron, 0,17 und 0,07ng/ml für Androstendion sowie 1,7 und 0,9ng/ml für Epitestosteron. Die Gn‐RH‐Applikation bewirkte einen Anstieg aller untersuchten Hormone, der bei LH bereits 30 Minuten nach der Verabreichung ein Maximum von 17,3ng/ml erreichte. Die Androgenkonzentrationen stiegen erst später an und erreichten erst 2 Stunden nach der Gn‐RH‐Applikation Maximalwerte von 8,1 ng/ml für Testosteron, 0,3 ng/ml für Androstendion und 2,0 ng/ml für Epitestosteron. Epitestosteron ist somit im peripheren Blut ein Parameter der testikulären Androstendionsekretion. Summary Androstendione, Epitestosterone, Testosterone and Luteinizing Hormone in Plasma of steers before and after administration of GnRH (Lutal®) In 9 spotted steers aged 8–12 months blood samples were taken over a period of 6 hours and the concentrations of LH, testosterone, androstendione and epistestosterone were determined by radioimmunoassay. On the following day the steers received 100μg Gn‐RH (Lutal®) intramuscularly and the hormone concentrations were again measured. During the 6‐hours period the hormone concentrations in the blood of the steers varied between 3.3 and 1.72 ng/ml for LH and 4.2 and 1. 0ng/ml for testosterone, 0.17 and 0.07 ng/ml for androstendione and 1.7 and 0.9 ng/ml for epitestosterone. Gn‐Rh administration caused a rise in all the hormones examined, which for LH 30 minutes after dosage reached a maximum of 17.3 ng/ml. The androgen levels took longer to rise and reached their maximal values 2 hours after Gn‐RH administration, when the maxima were for testosterone 8.1 ng/ml, for androstendione 0.3 ng/ml and for epitestosterone 2.0 ng/ml. Epitestosterone is thus, in peripheral blood, a parameter of testicular androstendione secretion. Résumé Androstendione, épitestostérone, testostérone et hormone lutéinisante dans le plasma sanguin de taureaux avant et après application de Gn‐RH (Lutal®) On a mesuré par Radioimmunoassay la concentration en LH, testostérone, androstendione et épitestostérone dans des échantillons de sang prélevés toutes les six heures chez neuf taureaux tachetés âgés de huit à douze mois. Les taureaux ont reçu chacun le jour suivant 100μg Gn‐RH (Lutal®) par voie intramusculaire et on a denouveau déterminé la concentration des hormones citées. Les concentrations d'hormones mesurées à six heures d'intervalle ont varié de la manière suivante dans le sang des taureaux: entre 3,3 et 1,72 ng/ml pour LH, 4,2 et 1,0 ng/ml pour la testostérone, 0,17 et 0,07 ng/ml pour l'androstendione et 1,...

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Plasma androstenedione after injections of dexamethasone and luteinizing hormone releasing hormone in young post-pubertal bulls

Cited by 2 publications

References 17 publications

Individual variations in FSH release after a GnRH challenge and relationship with semen output in young bulls

Individual variations in FSH release after a GnRH challenge and relationship with semen output in young bulls

Androstendion, Epitestosteron, Testosteron und Luteinisierungshormon im Blutplasma von Stieren vor und nach Verabreichung von Gn‐RH (Lutal®)³

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Plasma androstenedione after injections of dexamethasone and luteinizing hormone releasing hormone in young post-pubertal bulls

Cited by 2 publications

References 17 publications

Individual variations in FSH release after a GnRH challenge and relationship with semen output in young bulls

Individual variations in FSH release after a GnRH challenge and relationship with semen output in young bulls

Androstendion, Epitestosteron, Testosteron und Luteinisierungshormon im Blutplasma von Stieren vor und nach Verabreichung von Gn‐RH (Lutal®)3

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Androstendion, Epitestosteron, Testosteron und Luteinisierungshormon im Blutplasma von Stieren vor und nach Verabreichung von Gn‐RH (Lutal®)³