Browse > Article

Reproductive Biology of the Seals in Polar Region: Spermatogenesis  

Gye Myung-Chan (Department of Life Sience, College of Natural Sciences, Hanyang University)
Kang Sung-Ho (Korea Polar Research Institute, KORDI)
Publication Information
Korean Journal of Environmental Biology / v.24, no.1, 2006 , pp. 1-6 More about this Journal
Abstract
Abstract - Global decline in wildlife mammals has been accelerated during past decades. Especially the conservation the wild life mammals in polar areas, is urgent. In an effort to understand the reproduction of the seals dwelling in the polar area, spermatogenesis in the seals was reviewed. Seals breed seasonally and in most of the seal species, delayed implantation is frequently observed. To date, histological and endocrinological evaluation revealed highly cyclic nature in supermatogenesis and steroidogenesis in testis. Seasonal changes in blood testosterone level together with melatonin is closely related with changes in light cycle between summer and winter. In adult testis at breeding seasons, spermatogenesis is manifested by consecutive 18 stages of germ cell development. Three kinds of Leydig cells different in steroidogenic activity as well as cellular morphology appear during the testis development. During non-breeding season, spermatogenic arrest and Leydig cell hypoplasia are frequently found. Interestingly, blood circulation through the anastomoses of pelvic veins cooled the testes and thus guarantees spermatogenesis within the body trunk. Endocrine disruptors and heavy metals have been found in the body tissues of several seals species and alter steroidogenesis in seals, suggesting environmental pollutants together with decrease in habitats are potentially threatening the reproductive success in seal species.
Keywords
reproduction; spermatogenesis; seals;
Citations & Related Records
연도 인용수 순위
  • Reference
1 Daniel JC. Jr 1974. Circulating levels of oestradiol-17beta during early pregnancy in the Alaskan fur seal showing an oestrogen surge preceding implantation. J. Reprod. Fertil. 37:425-428   DOI   ScienceOn
2 Faria MJ, ZL Simoes, LO Lunardi and K Hartfelder. 2003. Apoptosis process in mouse Leydig cells during postnatal development. Microsc. Microanal. 9:68-73   DOI   ScienceOn
3 Kovacs KM. 2005. Birds and Mammals of Svalbard. Norweigian Polar Institute. Tromso
4 Laws RM. 1956. The elephant seal (Mirounga leonina L.). 2. General, social and reproductive behavior. Sci. Rep. Falkld. Isl. Depend. Surv. 13: 1-88
5 Mansfield AW. 1958. The breeding behaviour and reproductive cycle of the Weddell seal: (Leptonychotes weddelli Lesson). Sci. Rep. Falkld. Isl. Depend. Surv. 18: 1-41
6 Short RV and T Mann. 1966. The sexsual cycle of a seasonally breeding mammal, the roebuck (Capreolus carpreolus). J. Reprod. Fertil. 12:377-351   DOI   ScienceOn
7 Sinha AA, AW Erickson and Seal U.S. 1977. Fine structure of seminiferous tubules in antarctic seals. Cell Tissue Res. 178: 183-188
8 Temte JL. 1985. Photoperiod and delayed implantation in the northern fur seal (Callorhinus ursinus). J. Reprod. Fertil. 73:127-131   DOI   ScienceOn
9 Harrison RJ, LH Matthews and JM Roberts. 1952. Reproduction in some Pinnipedia. Trans. Zool. Soc. Lond. 27:437-540   DOI
10 Ashchepkova LIu and VIa Fedoseev. 1988. Development of male germ cells in the fur seal (Callorhinus ursinus). Arkh. Anat. Gistol. Embriol. 95:59-66
11 Erickson AW, HW Mossman, RJ Hensel and W A Troyer. 1968. The breeding biology of the male brown bear (U rsus arctos). Zoologica Sci. Contri., N.Y. Zool. Soc. 53:85-105
12 Leatherland JF and K Ronald. 1979. Structure of the testis in neonate and adult harp seals, Pagophilus groenlandicus. Cell Tissue Res. 201 :45-49
13 Simith MSR. 1966. Studies on the Weddell seal in McMurdo Sound, Antarctica. Ph.D. Thesis, pp. 1-161, University of Canterbury
14 Griffiths D, RF Seamark and MM Bryden. 1979. Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga leonina). Aust. J. Biol. Sci. 32:581-586   DOI
15 Oritsland T. 1970. Sealing and seals research in the Southwest Antartic pack ice, September-October 1964. vol 1, pp. 367-376. In Antartic Ecology (Holdgate MW ed.). Academic Press. New York
16 Boyd IL. 1991. Changes in plasma progesterone and prolactin concentrations during the annual cycle and the role of prolactin in the maintenance of lactation and luteal development in the Antarctic fur seal (Arctocephalus gazella). J. Reprod. Fertil. 91:637-647   DOI   ScienceOn
17 Russell LD, RA Ettlinm, AP Sinha-Hikim and ED Clegg. 1990. Histological and Histopathological Evaluation of the Testis. Cache River Press, Clearwate, FL
18 Ashchepkova LIu. 1990. Spermatogenic cycle in seals (Callorhinus ursinus L.). Arkh. Anat. Gistol. Embriol. 98:79-82
19 Daniel JC. Jr 1981. Delayed implantation in the northern fur seal (Callorhinus ursinus) and other pinnipeds. J. Reprod. Fertil. Suppl. 29:35-50
20 Freeman HC and GB Sangalang. 1977. A study of the effects of methyl mercury, cadmium, arsenic, selenium, and a PCB, (Aroclor 1254) on adrenal and testicular steroidogeneses in vitro, by the gray seal Halichoerus grypus. Arch. Environ. Contam. Toxicol. 5:369-383   DOI
21 Troisi GM and CF Mason. 2000. PCB-associated alteration of hepatic steroid metabolism in harbor seals (Phoca vitulina). J. Toxicol. Environ. Health. A 61 :649-655   DOI
22 Gibbney L. 1953. Delayed implantation in the elephant seal. Nature 172:590-591   DOI   ScienceOn
23 Rommel SA, GA Early, KA Matassa, DA Pabst and W A McLellan. 1995. Venous structures associated with thermoregulation of phocid seal reproductive organs. Anal. Rec.243:390-402   DOI   ScienceOn
24 Hall AJ, OI Kalantzi and GO Thomas. 2003. Polybrominated diphenyl ethers (PBDEs) in grey seals during their first year of life: Are they thyroid hormone endocrine disrupters? Environ. Pollut. 126:29-37   DOI   ScienceOn
25 Sinha AA, A W Erickson and US Seal. 1977. Fine structure of Leydig cells in crabeater, leopard and Ross seals. J. Reprod. Fertil. 49:51-54   DOI   ScienceOn
26 Stirling I. 1971. Population dynamics of the Weddell seal (Leptonychotes weddelli) in McMurdo Sound, Antarctica, 1966-1968. Antarctic Res. 18:141-161
27 Lopes FL, JA Desmarais and BD Murphy. 2004. Embryonic diapause and its regulation. Reproduction 128:669-678   DOI   ScienceOn
28 Davidoff MS, R Middendorff, G Enikolopov, D Riethmacher, AF Holstein and D Muller. 2004. Progenitor cells of the testosterone-producing Leydig cells revealed. J. Cell Biol. 167:935-944   DOI   ScienceOn
29 Joffre J and M Joffre. 1973. Seasonal changes in the testicular blood flow of seasonally breeding mammals: Dormouse, Glis glis, ferret, Mustella fero, and fox, Vulpes vulpes. J. Reprod. Fertil. 34:227-233   DOI   ScienceOn