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ABSTRACT: The pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-related family and occurs in two amidated forms, PACAP38 and PACAP27, with 38 and 27 amino acids, respectively. PACAP acts by binding to three different receptors, that are classified by their binding affinity for PACAP and VIP (vasoactive intestinal polypeptide): PAC(1) R (PACAP-specific receptor) exclusively binds PACAP, while VPAC(1) R (VIP/PACAP receptor, subtype 1) and VPAC(2) R (VIP/PACAP receptor, subtype 2) bind both PACAP and VIP. PACAP, first discovered in the brain, was then localized in several peripheral tissues of mammals, including the ovary. Besides mammals, PACAP and its receptors have been reported in fish too; however, less is known about the presence of PACAP in the fish ovary and the studies are limited to teleosts. The aim of our work was to study the distribution of the PACAP/PACAP-Rs system in the ovary of the cartilaginous fish Torpedo marmorata. Using in situ hybridization (ISH) and immunohistochemistry techniques, we demonstrated that PACAP and its receptors are widely represented in the Torpedo ovary in a stage-dependent manner. Moreover, our findings suggest an involvement of this peptide in the whole follicologenesis, probably influencing steroidogenesis, follicle development, and oocyte growth. J. Exp. Zool. 9999A:1-9, 2012. © 2012 Wiley Periodicals, Inc.
Journal of Experimental Zoology Part A Ecological Genetics and Physiology 10/2012; · 1.64 Impact Factor
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ABSTRACT: The aim of this work was to study, by immunoprecipitation, in situ hybridization and immunohistochemistry, and the expression of the vasoactive intestinal peptide (VIP) and of its receptors (VPAC(1)R and VPAC(2)R) in the testis of a nonmammalian vertebrate, the cartilaginous fish Torpedo marmorata. We demonstrated that, differently from mammals, VIP and VPAC(2)R were widely distributed in the testicular cells while the VPAC(1)R had a limited distribution. In details, we showed that VIP and VPAC(2)R were present in mitotic and differentiating germ cells as well as in the cells involved in the steroidogenesis, i.e., Leydig, Sertoli cells, and prespermatogonia and spermatogonia. The possibility that VIP is involved in the spermatogenesis and particularly in the steroidogenesis of T. marmorata is discussed.
Journal of Molecular Neuroscience 07/2012; 48(3):638-46. · 2.50 Impact Factor
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ABSTRACT: The aim of this study is to assess, by RT-PCR, in situ hybridization, electron microscopy, and immunohistochemistry, the site/s of vitellogenin (VTG) synthesis in the mussel Mytilus galloprovincialis. Our investigations demonstrate that, among the analyzed tissues, the synthesis of VTG occurs only in the female gonad, i.e. within the oocyte and follicle and connective cells. Such a synthesis is just evident in early vitellogenic oocytes, whose cytoplasm is characterized by numerous RER cisternae and an extended Golgi complex surrounded by nascent yolk platelets. The synthesis of VTG goes on in vitellogenic oocytes assuming a pear form, and progressively reduces once the oocyte shows the pear or polygonal form, typical of those oocytes that have concluded the growth. The expression of VTG occurs also within follicle (auxiliary) and connective cells. In particular, it is noteworthy that follicle cells are characterized by numerous RER cisternae and an active Golgi complex surrounded by numerous vesicles and vacuoles containing electron dense material. The same material is also present along their plasma membrane, within the intercellular space between oocyte and follicle cells, and finally within invaginations of the oocyte surface, thus suggesting a VTG transfer to the oocyte via endocytosis. Differently, no VTG synthesis was observed within digestive gland. All together the findings here reported strongly suggest that in Mytilus galloprovincialis, inside the gonad, the VTG synthesis occurs in the oocyte (autosynthesis) and in the follicle and adipogranular cells (heterosynthesis). J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.
Journal of Cellular Physiology 07/2012; · 3.87 Impact Factor
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ABSTRACT: In vertebrates, the liver was long thought to be the only site of vitellogenin (Vtg) production, but recent studies demonstrated that Vtg is also expressed in extrahepatic districts. The aim of this paper is to assess, by in situ hybridization and immunohistochemistry, the expression of Vtg in the testis and kidney of Torpedo marmorata exposed to 17β-estradiol (E(2)). In treated samples vtg mRNA and Vtg were detected contemporaneously only in the testis; differently the kidney cells were positive to Vtg antibody, but negative to vtg mRNA. This is the first study to assess that male germ cells, after an exposure to E(2), synthesize Vtg in a stage-dependent manner. The presence of Vtg and the modifications observed in the kidney after E(2) treatment are discussed.
General and Comparative Endocrinology 12/2011; 174(3):318-25. · 3.27 Impact Factor
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ABSTRACT: The aim of this investigation was to identify the encoding sequence of vitellogenin receptor gene (vtgr), and its expression during the oogenesis in the spotted ray, Torpedo marmorata, in different phases of reproductive cycle. From an ovarian cDNA of vitellogenic female, we obtained a fragment of 581 bp, which corresponds to a partial sequence encoding the vitellogenin receptor (VTGR) in Torpedo (accession number: gi/193244760). This sequence shows a high identity with the VTGR of other vertebrates, particularly Leucoraja erinacea (89% identity) and Squalus acanthias (84% identity). We also showed that vtgr mRNA expression in the ovary modifies during the oogenesis and throughout the reproductive cycle. Indeed, in immature females, whose ovary contains only previtellogenic follicles, vtgr mRNA occurred in the oocyte cortex as well as within intermediate and pyriform cells. In mature females, whose ovary contains pre- and vitellogenic follicles, vtgr mRNA was detectable not only in the oocyte cortex and in intermediate and pyriform cells but also in small follicle cells present in the follicular epithelium of vitellogenic follicles. In ovulating females, that, as pregnant ones, show pre-and vitellogenic follicles, vtgr mRNA was evident in the oocyte cortex only, whereas in pregnant females, no vtgr mRNA was evident. The role of VTGR in the control of Torpedo vitellogenesis is discussed.
Journal of Experimental Zoology Part A Ecological Genetics and Physiology 12/2011; 315(10):585-92. · 1.64 Impact Factor
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ABSTRACT: The pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-related family that occurs in two amidated forms with 38 (PACAP38) and 27 (PACAP27) amino acids. First discovered in the brain, it was then localized in several peripheral tissues of mammals, including the testis. However, current knowledge of the expression and function of PACAP and its receptor PAC(1) in the reproductive system of non-mammalian vertebrates, and particularly in the testis, is still limited. The aim of this work was to study the presence of PACAP and its receptor PAC(1) in the testis of two non-mammalian vertebrates during the breeding season: the crested newt Triturus carnifex and the wall lizard Podarcis sicula. The expression and distribution of this neuropeptide and its receptor PAC(1) were investigated by using in situ hybridization and immunohistochemistry techniques. Our results demonstrated that PACAP and its receptor PAC(1) were highly represented in the testis of these two species. In particular, we showed that they are present within some germ cells and that PACAP, unlike in mammals, is expressed also in the somatic cells (Sertoli and Leydig cells) of the testis of these two non-mammalian vertebrates, suggesting that this neuropeptide is involved in the hormonal control of spermatogenesis and steroidogenesis.
General and Comparative Endocrinology 03/2010; 168(2):256-61. · 3.27 Impact Factor
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ABSTRACT: In this study, we show that Prothymosin alpha (Ptma), a small, unfolded, negatively charged protein, is present in the cartilaginous fish Torpedo marmorata. The ptma gene is functional and peculiarly controlled during the male spermatogenesis of T. marmorata, as revealed by in situ hybridization and by immunocytochemistry studies. The data show that the ptma transcript is present in stage-specific germ cells, i.e. spermatocytes II and round spermatids. The Ptma protein is detectable in spermatocytes II, in round and elongated spermatids as well as in spermatozoa before their release from cysts, while it is not evident in spermatozoa located in male genital tracts. The ptma transcript and protein are also evident in some Leydig cells, located among maturing cysts containing meiotic and differentiating male cells. No expression for ptma is observed within Sertoli cells. Furthermore, immunolocalization procedures demonstrate that the protein is preferentially localized in the cytoplasm, whereas a nuclear localization is observed in round and elongated spermatids. The possibility that Ptma is involved in testis activity is discussed.
General and Comparative Endocrinology 06/2009; 164(1):70-6. · 3.27 Impact Factor
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ABSTRACT: In Torpedo marmorata, the vitelline envelope (VE), an extracellular envelope surrounding the growing oocyte, consists of fibrils and amorphous materials that are deposited in the perivitelline space starting from the initial steps of oocyte growth. SDS-PAGE analysis of the isolated and purified VE reveals that it consists of different glycoproteins. Furthermore, our investigations showed that the 120 and 66 kDa glycoproteins are positive to an antibody directed against gp69/64 of the Xenopus laevis VE and are synthesized under the control of 17beta-estradiol in the liver, that, together follicle cells and the oocyte, is the biosynthetic site of VE components.
Journal of Experimental Zoology Part B Molecular and Developmental Evolution 05/2009; 312(7):714-21. · 2.42 Impact Factor
