Diurnal Fluctuations of Testosterone and Lh in the Ram: Effect of HCG and Gonadotrophin-Releasing Hormone

Falvo, Richard E.; Buhl, Allen E.; Reimers, T. J.; Foxcroft, G. R.; Dunn, M. Hunzicker; Dziuk, P. J.

doi:10.1530/jrf.0.0420503

Cited by 27 publications

(17 citation statements)

References 16 publications

(25 reference statements)

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“…(Lincoln, 1979 (Terqui et al, 1980). Findings of an apparent absence of relationship between LH and testosterone levels in rams may only be the result of too infrequent sampling (Falvo et al, 1975 The present results confirm that the numbers of LH and testosterone peaks increase from the non-breeding to the breeding season (Sanford et al, 1974(Sanford et al, , 1977Schanbacher & Ford, 1976;Wilson & Lapwood, 1978 …”

Section: Determination Oflh and Testosterone Peakssupporting

confidence: 78%

“…In the ram, LH and testosterone are released into the blood in a pulsatile pattern (Attal, 1970 Bolt, 1971; Katongole, Naftolin & Short, 1974: Sanford, Winter, Palmer & Howland, 1974 Falvo, et al, 1975), and each peak of LH is followed by a peak of testosterone (Lincoln, 1976 Sanford, Palmer & Howland, 1977;Wilson & Lapwood, 1978). There is general agreement that the number of LH and testosterone peaks increases when animals pass from the non-breeding season to the breeding season (Sanford et al, 1974(Sanford et al, , 1977Schanbacher & Ford, 1976;Wilson & Lapwood, 1978).…”

Section: Introductionmentioning

confidence: 99%

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Seasonal variation in LH and testosterone release in rams of two breeds

Pelletier¹,

Garnier²,

Reviers³

et al. 1982

Reproduction

122

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Section: Determination Oflh and Testosterone Peakssupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Seasonal variation in LH and testosterone release in rams of two breeds

Pelletier¹,

Garnier²,

Reviers³

et al. 1982

Reproduction

122

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“…The observation that hCG stimulated T production is in agreement with the earlier reports (4,9,25). In addition, the levels of A4A, a precursor of T, and 5a-DHT, a metabolite of T, were also increased after hCG treatment.…”

Section: Resultssupporting

confidence: 92%

“…Human chorionic gonadotrophin (hCG), which exerts similar biological effects to LH, has been shown to increase the peripheral (15,24) testis (6) and the rete testis fluid testosterone (T) concentrations (14) in the rat. Likewise, hCG elevates T levels in the mouse (4), ram (5,9), rabbit (20), bull (25), boar (2) and in human (10,11,27). However, it is not known if it affects also androgen metabolism.…”

Section: Introductionmentioning

confidence: 99%

Effects of hCG on Serum Levels of Testosterone, Dihydrotestosterone and Androstenedione in Male Mice

1978

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The concentrations of testosterone (T), 5α-dihydrotestosterone (5α-DHT) and Δ⁴-androstenedione (Δ⁴A) in the circulating blood were increased by a single subcutaneous injection of 10 IU of hCG in the mouse. The response of androgen synthesis to hCG stimulation was rapid and persisted over a period of 96 h. The increased supply of T to the peripheral organ(s) under the stimulation of hCG might contribute to an increase in circulating 5α-DHT. However, the changes in T/5α-DHT ratio implies that the stimulation of T and 5α-DHT production by hCG were not of the same degree.

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“…Functional Leydig cells synthesize T following hCG administration. This test has been validated for the bull [9], ram [10], boar [11], stallion [12] and human [13]. However, the profiles of plasma T concentrations after an hCG stimulation test have not been shown to be invariably similar, especially among prepubertal children [14] and bulls with cryptorchidism [15].…”

mentioning

confidence: 99%

Anti-Müllerian Hormone (AMH) Profiles as a Novel Biomarker to Evaluate the Existence of a Functional Cryptorchid Testis in Japanese Black Calves

Kitahara

Ali

Sato

et al. 2012

Journal of Reproduction and Development

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Abstract. Anti-Müllerian hormone (AMH) and testosterone (T) profiles in blood were investigated before and after an hCG stimulation test to assess their sensitivity and specificity for the existence of a functional cryptorchid testis in Japanese Black calves. The hCG (3,000 IU) was administered on Day 0, and peripheral blood was collected on Days 0 (just before hCG injection), 5 and 7 in intact male calves (Intact; n=19), bilateral castrated calves (Castrated; n=17), unilateral cryptorchid calves, which abdominal testis could been extracted (Uni-crypto; n=9). Castration of a descended testis was carried in the Castrated and Uni-Crypto groups on Day -14. The AMH detectability and the optimum cut-off point for T levels using the receiver operating characteristic curve were verified to characterize the cryptorchid testis. AMH values on Day 0 were 21.1 ± 5.1 and 29.0 ± 7.5 ng/ml in the Intact and Uni-crypto groups, respectively (Mean ± SEM). AMH levels were under the detection limit in the Castrated group (i.e., < 0.006 ng/ml). T showed its peak levels on Day 5 in the Intact group (26.8 ± 4.2 ng/ml), while it remained low in the Castrated group (< 0.9 ng/ml) and did not show a significant difference in the Uni-crypto group. The detectable levels for AMH was 0.006 ng/ml, and the optimum cut-off point for T was 0.9 ng/ml; the sensitivity and specificity for evaluation of testicular descent into the scrotum were 1.0 for both the AMH and T levels. The detection rates in the Uni-crypto group using them were 1.0 and 0.57 for AMH on Day 0 and T on Days 5 or 7, respectively. In conclusion, plasma AMH profiles could be used as a novel biomarker to evaluate the existence of a functional cryptorchid testis in Japanese Black calves. Key words: Anti-Müllerian hormone (AMH), Bovine cryptorchidism, hCG stimulation test, Receiver operating characteristic, Testosterone (J. Reprod. Dev. 58: [310][311][312][313][314][315] 2012) C ryptorchidism is the failure of one or both testes to descend into the scrotum during the first trimester of pregnancy [1]. The plausible causes of cryptorchidism include insufficient secretion of insulin-like peptide 3 and/or testosterone (T) [1]. Cryptorchidism is most common in stallions, boars and some breeds of canine, but is rare in most other species [2,3]. The rate of morbidity with cryptorchidism in cattle is 0.2% [4]. The internal body temperature that surrounds the intra-abdominal retained testes associated with cryptorchidism is higher in comparison with that in the scrotum; this compromises spermatogenesis [5].Calves with a cryptorchid testis are commonly detected at castration [3]. If they have unilateral cryptorchid testes, the contralateral descended testes are extracted on the same day, and the cryptorchid testis is then usually looked for by laparotomy on another day. However, exteriorization of an abdominal testis is difficult [6].Fattening bulls with cryptorchidism in the later growing stages usually result in bulls with a stout body type that exhibit masculine characteristics in the ne...

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Diurnal Fluctuations of Testosterone and Lh in the Ram: Effect of HCG and Gonadotrophin-Releasing Hormone

Cited by 27 publications

References 16 publications

Seasonal variation in LH and testosterone release in rams of two breeds

Seasonal variation in LH and testosterone release in rams of two breeds

Effects of hCG on Serum Levels of Testosterone, Dihydrotestosterone and Androstenedione in Male Mice

Anti-Müllerian Hormone (AMH) Profiles as a Novel Biomarker to Evaluate the Existence of a Functional Cryptorchid Testis in Japanese Black Calves

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