Navegando por Palavras-chave "reproduction"

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    Characterization of four substrates emphasizes kinetic similarity between insect and human C-domain angiotensin-converting enzyme
    (Blackwell Publishing Ltd, 2002-07-01) Hens, K.; Vandingenen, A.; Macours, N.; Baggerman, G.; Carmona, Adriana Karaoglanovic [UNIFESP]; Schoofs, L.; De Loof, A.; Huybrechts, R.; Catholic Univ Louvain; Universidade Federal de São Paulo (UNIFESP)
    Angiotensin converting enzyme (ACE) was already discovered in insects in 1994, but its physiological role is still enigmatic. We have addressed this problem by purifying four new ACE substrates from the ovaries of the grey fleshfly, Neobellieria bullata . Their primary structures were identified as NKLKPSQWISLSD (Neb -ODAIF- 1(1-13) ), NKLKPSQWI (Neb -ODAIF- 1(1-9) ), SLKPSNWLTPSE (Neb -ODAIF- 2) and LEQIYHL. Database analysis showed significant homology with amino acid sequence stretches as present in the N-terminal part of several fly yolk proteins. An antiserum raised against Neb -ODAIF-1(1-9) immunostained one out of three yolk protein bands of SDS/PAGE-separated fly haemolymph and egg homogenate, thus confirming that these peptides originate from a yolk protein gene product. Kinetic analysis of these peptides and of the peptides Neb -ODAIF and Neb -ODAIF- 1(1-7) with insect ACE and human ACE show both similar and unique properties for insect ACE as compared with human C-domain ACE.
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    Estrogen receptors and function in the male reproductive system
    (Sociedade Brasileira de Endocrinologia e Metabologia, 2009-11-01) Lazari, Maria de Fatima Magalhaes [UNIFESP]; Lucas, Thais Fabiana Gameiro [UNIFESP]; Yasuhara, Fabiana [UNIFESP]; Gomes, Gisele Renata Oliveira [UNIFESP]; Siu, Erica Rosanna [UNIFESP]; Royer, Carine [UNIFESP]; Fernandes, Sheilla Alessandra Ferreira [UNIFESP]; Porto, Catarina Segreti [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    A substantial advance in our understanding on the estrogen signaling occurred in the last decade. Estrogens interact with two receptors, ESR1 and ESR2, also known as ERα and ERβ, respectively. ESR1 and ESR2 belong to the nuclear receptor family of transcription factors. In addition to the well established transcriptional effects, estrogens can mediate rapid signaling, triggered within seconds or minutes. These rapid effects can be mediated by ESRs or the G protein-coupled estrogen receptor GPER, also known as GPR30. The effects of estrogen on cell proliferation, differentiation and apoptosis are often mediated by growth factors. The understanding of the cross-talk between androgen, estrogen and growth factors signaling pathways is therefore essential to understand the physiopathological mechanisms of estrogen action. In this review we focused on recent discoveries about the nature of the estrogen receptors, and on the signaling and function of estrogen in the male reproductive system.
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    Impairment of male reproductive function after sleep deprivation
    (Elsevier B.V., 2015-05-01) Alvarenga, Tathiana A. [UNIFESP]; Hirotsu, Camila [UNIFESP]; Mazaro-Costa, Renata; Tufik, Sergio [UNIFESP]; Andersen, Monica L. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Federal de Goiás (UFG)
    Objective: To evaluate the influence of sleep loss on sexual behavior, hormone levels, sperm parameters, and testis-specific gene expression in male rats.Design: Experimental research.Setting: Animal laboratory.Animal(s): Male adult Wistar-Hannover rats.Intervention(s): Sexually experienced rats were subjected to paradoxic sleep deprivation (PSD) for 96 hours or sleep restriction (SR) for 21 days or kept in their home cage as control (CTRL).Main Outcome Measure(s): Sexual behavior, hormone levels, sperm parameters and expression of stress and nitric oxide-related genes were evaluated.Result(s): PSD significantly decreased sexual behavior compared with the CTRL group, whereas SR had no effect. the PSD group had significantly lower testosterone levels than the CTRL group. Both PSD and SR groups had lower sperm viabilities than the CTRL group. the decrease in the number of live sperm compared with the CTRL group was larger in the PSD group than in the SR group. Regarding testicular gene expression, both PSD and SR led to an increase of iNOS and hydroxysteroid 11 beta-dehydrogenase 1 expressions compared with the CTRL group. These changes were more pronounced in the PSD group. A significant increase in endothelial nitric oxide synthase expression was observed in the PSD groups compared with the CTRL group. No changes were observed in dimethylarginine dimethylaminohydrolase 1 and casein kinase 2 beta-polypeptide expressions.Conclusion(s): Sleep loss can promote marked changes in the male reproductive system of rats, particularly affecting spermatic function in part by interfering in the testicular nitric oxide pathway. (C) 2015 by American Society for Reproductive Medicine.
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    Mating plugs and male sperm storage in Bothrops cotiara (Serpentes, Viperidae)
    (British Herpetol Soc, 2017) Barros, Veronica A.; Rojas, Claudio Augusto [UNIFESP]; Almeida-Santos, Selma M.
    We describe two new aspects of male reproduction in the pit viper Bothrops cotiara: the formation of mating plugs and epididymal sperm storage. Based on histological analyses of specimens (four males and three females), we propose that long-term sperm storage occurs in the ductus deferens, whereas macroscopic hypertrophy indicates that the epididymis may be a short-term sperm storage site. Secretions of the sexual segment of the kidneys probably form the mating plug that males deposit in the female vagina during copulation. A mating plug without sperm was observed in the spring. Future studies should address the functions and longevity of mating plugs and the role of the epididymis in Bothrops reproduction.