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

Malak, G. Abdel; Thibier, M.

doi:10.1530/jrf.0.0750345

Cited by 4 publications

(4 citation statements)

References 12 publications

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“…However, in the case of testosterone, GnRH challenges were necessary to detect corre¬ lations with testis size. Malak and Thibier (1985) also found negative correlations between GnRH-stimulated FSH and sperm output and quality in yearling bulls (r = -0.40 to -0.70), but only when the FSH response was amplified by a pretreatment with dexamethasone. These correlations are similar to the values described in the present study where FSH at 12 months of age increased from 0.44 ng ml " 1 (basal) to 0.95 ng ml"1 and 1.1 ng ml"1 at 1.5 and 3.0 h after GnRH, respectively.…”

Section: 85bmentioning

confidence: 78%

“…According to Malak and Thibier (1985), FSH concentration increased from 1.6 ng ml"1 to a maximum of 2.6 ng ml"1 after GnRH only (1.6-fold) and to 4.0 ng ml " (2.5-fold) after GnRH plus dexamethasone. Thus, the results presented here with GnRH only were similar to the response achieved with GnRH plus dexamethasone, in terms of both magnitude of FSH secretion and correlations with testis criteria.…”

Section: 85bmentioning

confidence: 98%

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Age-related changes in peripheral hormone concentrations and their relationships with testis size and number of Sertoli and germ cells in yearling beef bulls

Moura

Erickson²

1997

Reproduction

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A study was conducted to determine whether basal or GnRH-stimulated concentrations of FSH, LH, testosterone, androstenedione and oestradiol measured from 2 months to 12 months of age were correlated with size and histology of the testes of Angus bulls at 12 months of age. Three blood samples per month were taken from 24 calves at 1.5 h intervals to establish basal hormone concentrations. On the following day, calves received 0.05 microgram of GnRH kg-1 body mass and were bled 1.5 h and 3.0 h later. At 12 months of age, bulls were castrated and testes were measured and prepared for histological analysis. Yearling testis diameter was related to GnRH-stimulated testosterone at 3 months (r = 0.48, P < 0.05). Basal FSH at all ages between 2 months and 12 months was correlated with yearling testis diameter (r = -0.53, P < 0.05, to r = -0.74, P < 0.01). In addition, basal FSH, measured at 2 and 3 months and between 8 and 12 months, was related to number of Sertoli cells per testis (r = -0.47, P < 0.05, to r = -0.53, P < 0.05), number of round spermatids per A1 spermatogonium (r = -0.48, P < 0.05, to r = -0.60, P < 0.01) and number of round spermatids per Sertoli cell (r = -0.50, P < 0.05, to r = -0.64, P < 0.01). Similarly, prepubertal concentrations of GnRH-stimulated FSH between 2 months and 12 months of age were correlated with testis diameter (r = non-significant, to r = -0.71, P < 0.01) and cell ratios in the seminiferous tubules (r = non-significant, to r = -0.61, P < 0.01). Thus, prepubertal hormone secretion could serve as a meaningful index of the potential sperm-producing capacity of the yearling bull.

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Section: 85bmentioning

confidence: 78%

Section: 85bmentioning

confidence: 98%

Age-related changes in peripheral hormone concentrations and their relationships with testis size and number of Sertoli and germ cells in yearling beef bulls

Moura

Erickson²

1997

Reproduction

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“…0 How long after GnRH treatment (15,90 or 120 min) the second blood sample was taken. How often the consecutive GnRH treatments were given (12 h, 1-3 months) (Mongkonpunya et al 1975; M MQes, J T6zs6r, A Nagy, K Gerszi and Z Szakks Tannen and Convey 1977;Oltner et al 1979;Malak et al 1985;Gabor et al 1995).…”

Section: Introductionmentioning

confidence: 99%

“…The theoretical basis for that is the ability to measure the response of the different animals to the same dose of exogenous GnRH, given more comparable information about the testosterone production 'capacity' of testicles. 0 How long after GnRH treatment (15,90 Tannen and Convey 1977;Oltner et al 1979;Malak et al 1985;Gabor et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Some Andrological Parameters of Charolais Breeding Bulls in Self‐performance Test

Mézes

Tőzsér

Nagy

et al. 1997

Reprod Domestic Animals

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ContentsThe authors invcstigated the effect of age on GnRH induced testosterone response and its correlation with body weight and some morphometric traits such as scrotal circumference, width of chest, height of shoulder, depth of chest in Charolais breeding bull candidates at the beginning and the end of the self-performance test in an age matched group ( & 30 days).It was found that the correlation in the case of age and testosterone content of blood serum before and after GnRH treatment was low. The multiple correlation with morphomctric traits i s moderate which supports the well-known effect of testosterone on muscle formation.Moderate or close correlation was found in respect of GnRH test results and scrotal circumference and those correlation remained the same at the beginning and the end of the selfperformance test, which suggests the possibility of early selection of breeding bull candidates.The relatively high individual variance among the bulls in the case of GnRH test results and some morphometric traits suggest some endocrinological differences among the different types of bulls within the same genotype and it would be a possible marker for type-selection. Inhalt Einige andrologische Parameter bei Charolais-Zuchtbullen im EigenleistungstestEs wurde ein Alterseffekt auf die durch GnRH induzierte Testosteron-Antwort und die Korrclation zu Korpergewicht und einigen morphometrischen Parametcrn, wie Umfang des Hodensacks, Brustumfdng, Schulterhohe, Tiefe der Brust bci Charolais-Bullen zu Beginn und am Ende eines Eigenleistungstests in altersabhingigen Gruppen (+30 Tage) untersucht.Dabci wurde herausgefunden, dab die Korrelation zwischen Alter und Bluttestosterongehalt vor und nach GnRH-Behandlung nur schwach ausgespragt ist. Die multiple Korrelation zwischen morphometrischen Werten war eher maBig und bestatigt damit die gut bekannten Effekte von Testosteron auf die Muskelausbildung. Hinsichtlich der AbhBngigkeit von GnRH und Hodensackumfang wurden mittelmiiDige his hohe Korrelationen gefunden und waren zu Beginn und am Ende der Eigenleistungspriifung gleich. Hieraus la& sich die Moglichkeit ableiten, bei zuchtbullen eine friihe Sclektion vorzunehmen.Die relativ hohe individuelle Varianz zwischen Bullcn bei den GnRH-Ergebnissen und bei einigen morphologischen Ergebnissen lassen auf unterschiedliche endokrinologische Muster zwischen verschiedenen Rullentypen innerhalh des selben Genotyps schliel3en. Dieses kiinnte als moglicher Marker fur eine Typenselcktion verwendet wcrden.

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LH and testosterone responses to five doses of a GnRH analogue (buserelin acetate) in 12-month-old Thoroughbred colts

et al. 2004

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

Cited by 4 publications

References 12 publications

Age-related changes in peripheral hormone concentrations and their relationships with testis size and number of Sertoli and germ cells in yearling beef bulls

Age-related changes in peripheral hormone concentrations and their relationships with testis size and number of Sertoli and germ cells in yearling beef bulls

Some Andrological Parameters of Charolais Breeding Bulls in Self‐performance Test

LH and testosterone responses to five doses of a GnRH analogue (buserelin acetate) in 12-month-old Thoroughbred colts

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