Acquisition of Potential for Sperm Motility <i>in vitro</i> in Japanese Eel <i>Anguilla japonica</i>

Abstract

Sperm maturation is the development of spermatozoa from nonfunctional gametes to mature spermatozoa fully capable of vigorous motility and fertilization.1-4) Under conditions of cultivation, male Japanese eel

Comparative analysis of milt quality and steroid levels in blood and seminal fluid of Persian sturgeon males, Acipenser persicus during final maturation induced by hormonal treatment

“…In some teleosts such as japanese eel, Anguilla japonica Temminck et Schlegel, 1846, rainbow trout and Chum salmon, Oncorhynchus keta (Walbaum, 1792), it is suggested that 17α,20β-dihydroxy-4-pregnen-3-one (DHP) is related to the regulation of sperm maturation in SF (Miura et al 1991a, b;1992). In this regard, the DHP indirectly mediate the increasing of seminal plasma pH, which in turn increases the sperm content of cAMP, thereby allowing the acquisition of potential of motility (Miura et al 1991a(Miura et al , 1992(Miura et al , 1995. In Persian sturgeon and stellate (Bayunova et al 2006), the BS levels of DHP did not show significant change both in mature and non-mature males.…”

Molecular approaches related to the European eel (Anguilla anguilla) reproductive process

“…In the European eel, DHP seems to induce early spermatogonia to enter meiosis, through the membrane progestin receptors mPRγ and mPRδ, and the nuclear progestin receptor pgr2 in the testis (Fig 1). Concerning final sperm maturation, it seems that DHP act directly throught a membrane receptor localized in the spermatozoa to stimulate the carbonic anhydrase activity which causes an increase in the seminal plasma pH, which in turn increases the sperm content of cAMP, thereby allowing the acquisition of sperm motility (Miura et al 1991b(Miura et al , 1992(Miura et al , 1995(Miura et al , 2003a. According to our results, this effect of DHP on final sperm maturation may be mediated by the membrane progestin receptors mPRα, mPRAL1 and mPRAL2 (Fig 1).…”

“…However, while the reproductive functions of the PRs have been well studied in mammalian models, less information is available in teleost fish. In Japanese eel, progestins induce early spermatogonia to enter in the meiotic prophase , further regulating sperm maturation (Miura et al, 1995;Schultz et al, 2010). Both Pgr and mPRα were suggested to be involved at the beginning and/or at the final sperm maturation (Thomas et al, 2004;Tubbs et al, 2008;Chen et al, 2012;Tan et al, 2014).…”

“…According to Miura et al (1991bMiura et al ( , 1992Miura et al ( , 1995Miura et al ( , 2006 DHP is an essential hormone involved in the initiation of meiosis and in the regulation of final maturation. These results correspond to the DHP level measured in ours studies (Chapters 2 and 3) where an increase in eel DHP plasma levels has been observed between the proliferating spermatogonia and the spermatozoa stage.…”

“…It is known that in male fish two progestins: 17α,20β-dihydroxy-4-pregnen-3-one (DHP) and/or 17α,20β,21-trihydroxy-4-pregnen-3-one (20βS) are the maturation-inducing steroids (MIS), mediating the process of sperm maturation and spermiation . In Japanese and European eels, DHP has been proposed to be an essential factor for the meiosis initiation at the beginning of spermatogenesis Peñaranda et al, 2010), but also to regulate final sperm maturation through the increase of pH in the seminal plasma, which induces an increase in intracellular cAMP, making the sperm cells capable of motility and fertilization (Miura et al, 1995). Furthermore, it is known that progestins regulate spermiation in Salmonidae and Cyprinidae (Ueda et al, 1985), increase milt production in Moronidae (Asturiando et al, 2002) and Salmonidae (Baynes et al, 1985), and stimulate sperm motility in Anguillidae (Miura et al, 1995) and Sciaenidae (Tubbs et al, 2008).…”