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Effects of luteinizing hormone-releasing hormone and arginine-vasotocin on the sperm-release response of Günther's Toadlet, Pseudophryne guentheri.

Silla AJ - Reprod. Biol. Endocrinol. (2010)

Bottom Line: LHRHa administration was highly effective at inducing spermiation in P. guentheri, with 100% of hormone-treated males producing sperm during the experimental period.The administration of AVT alone or in combination with LHRHa resulted in the release of significantly lower sperm numbers.Overall, results from this study suggest that in P. guentheri, LHRHa is effective at inducing spermiation, but that AVT inhibits sperm-release.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Animal Biology, The University of Western Australia, Perth, Australia. Aimee.Silla@gmx.com

ABSTRACT

Background: Luteinizing hormone-releasing hormone (LHRH) is an exogenous hormone commonly used to induce spermiation in anuran amphibians. Over the past few decades, the LHRH dose administered to individuals and the frequency of injection has been highly variable. The sperm-release responses reported have been correspondingly diverse, highlighting a need to quantify dose-response relationships on a species-specific basis. This study on the Australian anuran Pseudophryne guentheri first evaluated the spermiation response of males administered one of five LHRHa doses, and second, determined whether AVT administered in combination with the optimal LHRHa dose improved sperm-release.

Methods: Male toadlets were administered a single dose of 0, 1, 2, 4 or 8 micrograms/g body weight of LHRHa. A 4 micrograms/g dose of AVT was administered alone or in combination with 2 micrograms/g LHRHa. Spermiation responses were evaluated at 3, 7 and 12 h post hormone administration (PA), and sperm number and viability were quantified using fluorescent microscopy.

Results: LHRHa administration was highly effective at inducing spermiation in P. guentheri, with 100% of hormone-treated males producing sperm during the experimental period. The number of sperm released in response to 2 micrograms/g LHRHa was greater than all other doses administered and sperm viability was highest in the 1 microgram/g treatment. The administration of AVT alone or in combination with LHRHa resulted in the release of significantly lower sperm numbers.

Conclusion: Overall, results from this study suggest that in P. guentheri, LHRHa is effective at inducing spermiation, but that AVT inhibits sperm-release.

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Total number of spermatozoa (× 103) released by males administered LHRHa (n = 10) over a 12 h sampling period. Data shown are untransformed mean ± SEM. Letters displayed are the result of a Tukey Kramer HSD post-hoc test of Log10 (x +1) transformed data. Treatments that share a letter are not significantly different from each other.
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Figure 2: Total number of spermatozoa (× 103) released by males administered LHRHa (n = 10) over a 12 h sampling period. Data shown are untransformed mean ± SEM. Letters displayed are the result of a Tukey Kramer HSD post-hoc test of Log10 (x +1) transformed data. Treatments that share a letter are not significantly different from each other.

Mentions: The total number of spermatozoa expelled over a 12 h period PA differed significantly according to dose treatment (one-way ANOVA, F4,49 = 43.16, p < 0.001; figure 2). The 2 μg/g treatment produced a significantly higher number of spermatozoa compared to the control and 8 μg/g treatments (Tukey-Kramer HSD, P < 0.05; figure 2), but was not significantly higher than to the 1 μg/g or 4 μg/g treatments (Tukey-Kramer HSD, P > 0.05; figure 2). In addition to the treatment effect identified for the total spermatozoa expelled, significant treatment effects were also detected at each of the individual sampling times, 3 h (one-way ANOVA, F4,49 = 13.22, p < 0.001), 7 h (Welch's ANOVA, F4 = 132.32, p < 0.001) and 12 h (Welch's ANOVA, F4 = 74.64, p < 0.001) PA. The number of spermatozoa expelled by males in the 2 μg/g treatment was consistently higher than the remaining treatments at all sampling periods PA (Tab. 2). Peak sperm-release occurred at 7 h PA for males administered 8 μg/g LHRHa, while all remaining dose treatments produced the highest number of spermatozoa at 12 h PA (Tab. 2). The total number of spermatozoa expelled was not related to the volume of urine collected or to toadlet mass (r2 = 0.003, p = 0.724; r2 = 0.008, p = 0.549, respectively).


Effects of luteinizing hormone-releasing hormone and arginine-vasotocin on the sperm-release response of Günther's Toadlet, Pseudophryne guentheri.

Silla AJ - Reprod. Biol. Endocrinol. (2010)

Total number of spermatozoa (× 103) released by males administered LHRHa (n = 10) over a 12 h sampling period. Data shown are untransformed mean ± SEM. Letters displayed are the result of a Tukey Kramer HSD post-hoc test of Log10 (x +1) transformed data. Treatments that share a letter are not significantly different from each other.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2992061&req=5

Figure 2: Total number of spermatozoa (× 103) released by males administered LHRHa (n = 10) over a 12 h sampling period. Data shown are untransformed mean ± SEM. Letters displayed are the result of a Tukey Kramer HSD post-hoc test of Log10 (x +1) transformed data. Treatments that share a letter are not significantly different from each other.
Mentions: The total number of spermatozoa expelled over a 12 h period PA differed significantly according to dose treatment (one-way ANOVA, F4,49 = 43.16, p < 0.001; figure 2). The 2 μg/g treatment produced a significantly higher number of spermatozoa compared to the control and 8 μg/g treatments (Tukey-Kramer HSD, P < 0.05; figure 2), but was not significantly higher than to the 1 μg/g or 4 μg/g treatments (Tukey-Kramer HSD, P > 0.05; figure 2). In addition to the treatment effect identified for the total spermatozoa expelled, significant treatment effects were also detected at each of the individual sampling times, 3 h (one-way ANOVA, F4,49 = 13.22, p < 0.001), 7 h (Welch's ANOVA, F4 = 132.32, p < 0.001) and 12 h (Welch's ANOVA, F4 = 74.64, p < 0.001) PA. The number of spermatozoa expelled by males in the 2 μg/g treatment was consistently higher than the remaining treatments at all sampling periods PA (Tab. 2). Peak sperm-release occurred at 7 h PA for males administered 8 μg/g LHRHa, while all remaining dose treatments produced the highest number of spermatozoa at 12 h PA (Tab. 2). The total number of spermatozoa expelled was not related to the volume of urine collected or to toadlet mass (r2 = 0.003, p = 0.724; r2 = 0.008, p = 0.549, respectively).

Bottom Line: LHRHa administration was highly effective at inducing spermiation in P. guentheri, with 100% of hormone-treated males producing sperm during the experimental period.The administration of AVT alone or in combination with LHRHa resulted in the release of significantly lower sperm numbers.Overall, results from this study suggest that in P. guentheri, LHRHa is effective at inducing spermiation, but that AVT inhibits sperm-release.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Animal Biology, The University of Western Australia, Perth, Australia. Aimee.Silla@gmx.com

ABSTRACT

Background: Luteinizing hormone-releasing hormone (LHRH) is an exogenous hormone commonly used to induce spermiation in anuran amphibians. Over the past few decades, the LHRH dose administered to individuals and the frequency of injection has been highly variable. The sperm-release responses reported have been correspondingly diverse, highlighting a need to quantify dose-response relationships on a species-specific basis. This study on the Australian anuran Pseudophryne guentheri first evaluated the spermiation response of males administered one of five LHRHa doses, and second, determined whether AVT administered in combination with the optimal LHRHa dose improved sperm-release.

Methods: Male toadlets were administered a single dose of 0, 1, 2, 4 or 8 micrograms/g body weight of LHRHa. A 4 micrograms/g dose of AVT was administered alone or in combination with 2 micrograms/g LHRHa. Spermiation responses were evaluated at 3, 7 and 12 h post hormone administration (PA), and sperm number and viability were quantified using fluorescent microscopy.

Results: LHRHa administration was highly effective at inducing spermiation in P. guentheri, with 100% of hormone-treated males producing sperm during the experimental period. The number of sperm released in response to 2 micrograms/g LHRHa was greater than all other doses administered and sperm viability was highest in the 1 microgram/g treatment. The administration of AVT alone or in combination with LHRHa resulted in the release of significantly lower sperm numbers.

Conclusion: Overall, results from this study suggest that in P. guentheri, LHRHa is effective at inducing spermiation, but that AVT inhibits sperm-release.

Show MeSH
Related in: MedlinePlus