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Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802)

This study examined the effects of testosterone (T) on the contractile properties of two sexually dimorphic forelimb muscles and one non-dimorphic muscle in male bullfrogs (Rana catesbeiana, Shaw 1802). The dimorphic muscles in castrated males with testosterone replacement (T(+)) achieved higher for...

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Autores principales: Kampe, Aaron R., Peters, Susan E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Company of Biologists 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3773340/
https://www.ncbi.nlm.nih.gov/pubmed/24143280
http://dx.doi.org/10.1242/bio.20133798
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author Kampe, Aaron R.
Peters, Susan E.
author_facet Kampe, Aaron R.
Peters, Susan E.
author_sort Kampe, Aaron R.
collection PubMed
description This study examined the effects of testosterone (T) on the contractile properties of two sexually dimorphic forelimb muscles and one non-dimorphic muscle in male bullfrogs (Rana catesbeiana, Shaw 1802). The dimorphic muscles in castrated males with testosterone replacement (T(+)) achieved higher forces and lower fatigability than did castrated males without replaced testosterone (T(0) males), but the magnitude of the differences was low and many of the pair-wise comparisons of each muscle property were not statistically significant. However, when taken as a whole, the means of seven contractile properties varied in the directions expected of masculine values in T(+) animals in the sexually dimorphic muscles. Moreover, these data, compared with previous data on male and female bullfrogs, show that values for T(+) males are similar to normal males and are significantly different from females. The T(0) males tended to be intermediate in character between T(+) males and females, generally retaining masculine values. This suggests that the exposure of young males to T in their first breeding season produces a masculinizing effect on the sexually dimorphic muscles that is not reversed between breeding seasons when T levels are low. The relatively minor differences in contractile properties between T(+) and T(0) males may indicate that as circulating T levels rise during breeding season in normal males, contractile properties can be enhanced rapidly to maximal functional levels for breeding success.
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spelling pubmed-37733402013-10-18 Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802) Kampe, Aaron R. Peters, Susan E. Biol Open Research Article This study examined the effects of testosterone (T) on the contractile properties of two sexually dimorphic forelimb muscles and one non-dimorphic muscle in male bullfrogs (Rana catesbeiana, Shaw 1802). The dimorphic muscles in castrated males with testosterone replacement (T(+)) achieved higher forces and lower fatigability than did castrated males without replaced testosterone (T(0) males), but the magnitude of the differences was low and many of the pair-wise comparisons of each muscle property were not statistically significant. However, when taken as a whole, the means of seven contractile properties varied in the directions expected of masculine values in T(+) animals in the sexually dimorphic muscles. Moreover, these data, compared with previous data on male and female bullfrogs, show that values for T(+) males are similar to normal males and are significantly different from females. The T(0) males tended to be intermediate in character between T(+) males and females, generally retaining masculine values. This suggests that the exposure of young males to T in their first breeding season produces a masculinizing effect on the sexually dimorphic muscles that is not reversed between breeding seasons when T levels are low. The relatively minor differences in contractile properties between T(+) and T(0) males may indicate that as circulating T levels rise during breeding season in normal males, contractile properties can be enhanced rapidly to maximal functional levels for breeding success. The Company of Biologists 2013-07-25 /pmc/articles/PMC3773340/ /pubmed/24143280 http://dx.doi.org/10.1242/bio.20133798 Text en © 2013. Published by The Company of Biologists Ltd http://creativecommons.org/licenses/by/3.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
spellingShingle Research Article
Kampe, Aaron R.
Peters, Susan E.
Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802)
title Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802)
title_full Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802)
title_fullStr Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802)
title_full_unstemmed Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802)
title_short Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802)
title_sort effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (rana catesbeiana, shaw 1802)
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3773340/
https://www.ncbi.nlm.nih.gov/pubmed/24143280
http://dx.doi.org/10.1242/bio.20133798
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