극지역 물개의 번식생물학: 정자형성

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 tounderstand the reproduction of the seals dwelling in the polar area, spermatogenesis in the sealsfrequently observed. To date, histological and endocrinological evaluation revealed highly cyclicnature in spermatogenesis and steroidogenesis in testis. Seasonal changes in blood testosteronelevel together with melatonin is closely related with changes in light cycle between summer andwinter. In adult testis at breeding seasons, spermatogenesis is manifested by consecutive 18 stagescellular morphology appear during the testis development. During non-breeding season,spermatogenic arrest and Leydig cell hypoplasia are frequently found. Interestingly, bloodcirculation through the anastomoses of pelvic veins cooled the testes and thus guaranteesspermatogenesis within the body trunk. Endocrine disruptors and heavy metals have been foundin the body tissues of several seals species and alter steroidogenesis in seals, suggestingreproductive success in seal species.