Effect of growth hormone and induced IGF-I release on germ cell population and apoptosis in the bovine testis

Santos, Renato L.; Silva, C.M; Ribeiro, A.F.C.; Vasconcelos, A.C.; Pesquero, Jorge Luiz; Coelho, Suelene; Serákides, Rogéria; Reis, Salomé

doi:10.1016/s0093-691x(99)00043-6

Cited by 25 publications

(21 citation statements)

References 26 publications

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“…However, the values were close to those found in Nelore cattle (4.8%; Cardoso and Godinho 1983), in various breeds (4.6%; Lennox and Logue 1979), and in young animals (29 months) of the Holstein breed (5.0%; Amann 1962); yet according to other studies, the values were higher than those of Nelore cattle (3.7%; Goiozo et al 2005) and lower than those observed in Holsteins (7.0%, Amann 1962). The zebu animals evaluated in this study had a mean diameter of the seminiferous tubules (251.4 µm) similar to that observed in 29-month-old Holstein bulls (254.0 µm) (Amann 1962) and higher than that observed in 4.9-year-old Nelore bulls (232.7 µm;Cardoso and Godinho 1983), 17-18-month-old Shorthorn bulls (210.4 µm;Swierstra 1966) and zebu animals without breed characterization (197.6 µm;Santos et al 1999). A larger tubular diameter was observed by Amann (1962) in mature Holstein bulls (269.0 µm); however, only two animals were assessed.…”

Section: Discussionsupporting

confidence: 59%

“…The values observed in Nelore (85.2%) and Polled Nelore (84.0%) bulls were higher than those observed by Cardoso and Godinho (1983) in Nelore bulls (81.4%), suggesting that the genetic selection applied to these breeds could have resulted in an increase in the volumetric proportion of the seminiferous tubules in the testicles. Much lower values were observed by Goiozo et al (2005), who reported 76.4% in pure-origin Nelore breeds, and by Santos et al (1999), who found 72.0% in zebu bulls without breed information. However, in these studies, the gross testicular weight, without subtracting the weights of the tunica albuginea and mediastinum was considered, which could have resulted in an underestimation of the values.…”

Section: Discussionmentioning

confidence: 68%

“…However, in these studies, the gross testicular weight, without subtracting the weights of the tunica albuginea and mediastinum was considered, which could have resulted in an underestimation of the values. In addition, the animals studied by Santos et al (1999) apparently were common animals of low genetic merit. Lower values were also observed in Holstein bulls, while a larger tubular volumetric proportion was found in younger animals (77.1-76.5%; 29 months-3 years old) compared to older animals (73.0%, 5.4 to 8.6 years old) (Amann 1962;Almquist and Amann 1962).…”

Section: Discussionmentioning

confidence: 99%

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Testicular Histomorphometric Evaluation of Zebu Bull Breeds

Andreussi

Faria

Fernandes

et al. 2014

Braz. arch. biol. technol.

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Section: Discussionsupporting

confidence: 59%

Section: Discussionmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 99%

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Testicular Histomorphometric Evaluation of Zebu Bull Breeds

Andreussi

Faria

Fernandes

et al. 2014

Braz. arch. biol. technol.

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“…In the bovine species, each A1 spermatogonium generates a theoretical number of sixty-four round spermatids (COUROT; HOCHEREAU-DE RIVIERS; ORTAVANT, 1970;APONTE;DE ROOIJ;BASTIDAS, 2005), indicating that there was a 47.5 % degeneration rate in the spermatogenesis of the Nelore bulls used in our study, playing a critical role in determining total sperm output. A previous study detected a germ cell degeneration rate of 33.6 % in Bos taurus bulls (based on the number of round spermatids/type A1 spermatogonium; MOURA; ERICKSON, 1997) and a publication by Santos et al (1999) reported a 16.5 % germ cell loss in Brazilian Zebu cattle. However, we cannot assume that Bos indicus bulls have either higher or lower rates of cell loss than Bos taurus bulls because the animals used in the studies cited above had different ages and weights as well as were raised and fed in very different conditions when compared to ours.…”

Section: Resultsmentioning

confidence: 93%

“…However, we cannot assume that Bos indicus bulls have either higher or lower rates of cell loss than Bos taurus bulls because the animals used in the studies cited above had different ages and weights as well as were raised and fed in very different conditions when compared to ours. Cell loss that occurs during spermatogenesis, due to apoptosis, has been reported in several species and it is caused by altered gene expression during mitosis and meiosis and/or external factors such as heat stress, chemical agents and nutritional imbalance (PRINT; LOVELAND, 2000;SOFIKITIS et al, 2008;CHENG et al, 2010). For the Nelore bulls, the average nucleus and nucleolus diameters of Sertoli cells were 8.4 ± 0.4 and 3.5 ± 0.2 μm, and those of spermatogonium reached 7.6 ± 0.5 and 3.3 ± 0.2 μm, respectively.…”

Section: Resultsmentioning

confidence: 99%

Testis size, peripheral concentrations of testosterone, semen criteria and Sertoli and germ cell numbers in Nelore bulls

et al. 2014

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A study was conducted to evaluate the associations among testis size, testosterone concentrations, semen parameters and aspects of spermatogenesis in Nelore bulls (n = 28). Testis size was measured from 10 to 29 months of age. Bulls were treated with GnRH (12 to 21 months) and semen samples also collected from 25 to 29 months. At 30 months, animals were slaughtered. Correlations were significant when p < 0.05. Basal testosterone was highest at 18 months, suggesting that bulls reached puberty at this age. At 30 months, seminiferous tubules represented 77.9 ± 3.8 % of the testicular parenchyma and there were 33.6 ± 8.4 round spermatids/A1 spermatogonium/tubule section, indicating a 47.5% degeneration rate during spermatogenesis. At 30 months, heavier testis correlated with Sertoli cell numbers/testis (r = 0.77), and round spermatids/tubule section, Sertoli cell and A1 spermatogonium (r = 0.50 -0.60). Scrotal circumference (SC) taken between 10 and 29 months correlated with the percentage of tubules with spermatids (r = 0.42 -0.59) and number of A1 spermatogonium and round spermatids/Sertoli cell (r = 0.49 -0.68). Epididymal weight was related to Sertoli cell numbers/testis, and round spermatids/ Sertoli cell and A1 spermatogonium (r = 0.51 -0.61). GnRH-stimulated testosterone from 17 to 21 months correlated with SC between 14 and 29 months (r = 0.48 -0.60), testis and epididymal weights (r = 0.41 -0.64) and with parameters of spermatogenesis (r = 0.44 -0.58). Additionally, sperm motility and vigor from 25 to 29 months correlated with the number of tubules with spermatids (r = 0.42 -0.59) and GnRH-stimulated testosterone at 12, 13 and 18 months (r = 0.46 -0.57). In conclusion, testis size during and after the period of pronounced increases in testosterone is an indicator of quantitative parameters of spermatogenesis of post-pubertal bulls. Key words: Nelore, sperm motility, spermatogenesis, testis, testosterone ResumoConduziu-se o presente estudo com o objetivo de avaliar as associações entre biometria testicular, testosterona, parâmetros seminais e aspectos da espermatogênese em touros Nelore (n = 28). Avaliou- se os testículos dos 10 aos 29 meses de idade. Os touros foram tratados com GnRH (12 a 21 meses) e amostras de sêmen coletadas (25 a 29 meses). Aos 30 meses, os animais foram abatidos. Correlações foram consideradas significativas quando p < 0.05. Concentrações elevadas de testosterona basal ocorreram aos 18 meses, indicativo da puberdade dos touros. Aos 30 meses, os túbulos seminíferos representaram 77,9 ± 3,8% do parênquima testicular e quantificou-se 33,6 ± 8,4 espermátides arredondadas/espermatogônia A1/secção tubular, referente a 47,5% de degeneração celular durante a espermatogênese. Aos 30 meses, peso testicular correlacionou-se com o número de células de Sertoli/ testículo (r = 0,77) e espermátides arredondadas/seção tubular, célula de Sertoli e espermatogônia A1 (r = 0,50 -0,60). A circunferência escrotal (CE) entre 10 e 29 meses correlacionou-se com a percentagem de túbulos com espermátide...

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Transgene transmission to progeny by oMt1a-oGH transgenic mice

2005

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Most studies utilizing transgenic technology focus on the impact to traits of interest, rather than propagation of the transgene to offspring. In animals containing growth hormone constructs, transgene transmission to progeny follows a Mendelian pattern of inheritance in the first few generations following generation of a founder animal, but decreases in subsequent generations. In the present study, the ovine metallothionein 1a-ovine growth hormone (oMt1a-oGH) transgenic mouse was used to determine whether transgene transmission rate to progeny was affected by overexpression of ovine growth hormone in the transgenic parent. The oMt1a-oGH mouse is a useful model for assessing transgene transmission, as the construct is easily regulatable and transgene inactivation results in a return of plasma GH to basal levels. Male and female hemizygous oMt1a-oGH mice were assigned to 1 of 3 treatment groups: (1) mice never actively expressing the transgene, (2) mice actively expressing the transgene from 3 weeks of age, and (3) mice actively expressing the transgene from 3 to 11 (males) or 3 to 8 (females) weeks of age. Transgenic mice were mated to wild type animals and the resulting progeny were genotyped. Males never actively expressing the transgene passed on the transgene to progeny in a Mendelian fashion, while males actively expressing the transgene transmitted the transgene to a smaller than expected number of progeny. However, following inactivation of the oMt1a-oGH construct in transgenic males, subsequent offspring demonstrated Mendelian inheritance of the transgene. In contrast, females expressing the transgene from 3 to 8 weeks of age were able to pass on the oMt1a-oGH construct in a Mendelian fashion, but females from other treatment groups were not. In oMt1a-oGH males, reduced transgene transmission appears to be due to selection against transgenic gametes. In females, however, selection against the transgenic genotype likely occurs at the embryonic level.

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Effect of growth hormone and induced IGF-I release on germ cell population and apoptosis in the bovine testis

Cited by 25 publications

References 26 publications

Testicular Histomorphometric Evaluation of Zebu Bull Breeds

Testicular Histomorphometric Evaluation of Zebu Bull Breeds

Testis size, peripheral concentrations of testosterone, semen criteria and Sertoli and germ cell numbers in Nelore bulls

Transgene transmission to progeny by oMt1a-oGH transgenic mice

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