Seasonal and developmental changes of reproductive organs of male ringed seals (Phoca hispida) in the Svalbard area |
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| Authors: | M. Ryg,,T. G. Smith, N. A. Ø ritsland |
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| Affiliation: | Division of General Physiology, University of Oslo, P.O. Box 1051, Blindern, 0316 Oslo 3, Norway;Fisheries and Oceans, Arctic Biological Station, Ste-Anne de Bellevue, Province de Québec, Canada H9X 3R4;Norwegian Polar Institute, Box 158, 1330 Oslo Lufthavn, Norway;and Division of General Physiology, University of Oslo, P.O. Box 1051, Blindern, 0316 Oslo 3, Norway |
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| Abstract: | The weights of testes, prostate gland and baculum of ringed seal males were related to age, season and differences in body size. There was a significant seasonal variation in testes and prostate gland size of sexually mature males, with a maximum occurring in early April. There were no seasonal changes in prostate weight of immature males, but some of the older immatures had elevated testes weights in April. Testes weight was significantly correlated with lean body mass. The increase in testes size with increasing body weight was greater for seals six years of age or older than for younger males. We suggest that some testicular growth and a seasonal cycle in testes growth occur before the testes become functional endocrinologically. We also believe that the primary event leading to puberty in ringed seals is an age-dependent shift in metabolic processes, directing a larger percentage of available energy towards the reproductive organs. |
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