Marcelo Castro Leal

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The zebrafish has become an important vertebrate model for basic and biomedical research, including the research field of the biology of reproduction. However, very few morphological and stereological data are available regarding zebrafish testis structure and spermatogenesis. In this careful histomorphometric evaluation of the testis, we studied(More)
The efficiency of Ovaprim™ salmon gonadotropin-releasing hormone agonist (GnRHa) and dopamine antagonist on the induction of spawning and spermiation in Prochilodus lineatus in comparison with the commonly used method using pituitary extract (PE) was evaluated. Females received PE at 0.5 + 5.0 mg/kg and Ovaprim™ at 0.05 + 0.45 ml/kg or at 0.125 + 0.375(More)
The wild boar is a natural inhabitant of Europe, Asia, and North Africa and is phylogenetically the ancestor of the domestic pig. Because of its phylogenetic and economic importance, this species is an interesting model for studying testis function in boars. Therefore, the present study was performed to investigate the testis structure, spermatogenic cycle(More)
Although the collared peccary (Tayassu tajacu) is found throughout the Americas, with a high potential for domestication and commercial exploitation, there are few data on the reproductive biology of this mammalian species. The aim of the present study was to investigate testis structure, spermatogenic cycle length, Sertoli cell efficiency, and(More)
The agouti (Dasyprocta leporina) and paca (Agouti paca) are among the largest extant rodent species. Although these species have considerable economic potential, there are few reports in the literature concerning male reproductive biology in sexually mature agoutis and pacas. The objectives of the present study were to perform detailed stereologic and(More)
To develop new tools to study the regulation of testis physiology in teleost fish, a medium-term ex vivo organ culture system was adopted for zebrafish testis tissue. The addition of 100nM 11-ketotestosterone to the system supported complete spermatogenesis, as determined by morphological, molecular and immunohistochemical analyses. Under basal conditions,(More)
In most eukaryotes, recombination of homologous chromosomes during meiosis is necessary for proper chromosome pairing and subsequent segregation. The molecular mechanisms of meiosis are still relatively unknown, but numerous genes are known to be involved, among which are many mismatch repair genes. One of them, mlh1, colocalizes with presumptive sites of(More)
Androgens can induce complete spermatogenesis in immature or prepubertal teleost fish. However, many aspects of the role of androgens in adult teleost spermatogenesis have remained elusive. Since oestrogens inhibit androgen synthesis, we used an oestrogen-induced androgen depletion model to identify androgen-dependent stages during adult zebrafish(More)
The aim of the present study was to characterize P450 17α-hydroxylase/17,20-lyase (cyp17a1) expression in zebrafish and to assess the effect of the pharmaceutical clotrimazole, a known inhibitor of various cytochrome P450 enzyme activities, on testicular gene and protein expression of this enzyme as well as on the testicular release of 11-ketotestosterone(More)
Although the goat is an economically important domestic mammal, there are very few data available in the literature for male reproductive biology in this species, mainly data related to testis morphometry obtained with high-quality light microscopy. Work recently developed in our laboratory found that the duration of the seminiferous epithelium cycle in(More)