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Id: lil-456598
Autor: Dapino, Dora G; Marini, Patricia e; Cabada, Marcelo O.
Título: Effect of heparin on in vitro capacitation of boar sperm
Fonte: Biol. Res;39(4):631-639, 2006. ilus, graf.
Idioma: en.
Resumo: Chlortetracycline (CTC) fluorescent pattern, the ability to undergo acrosome reaction (AR) upon exposure to 10 µM calcium ionophore A23187 and vitality estimation were used to investigate the effect of the sulfated glycosaminoglycan heparin on the in vitro capacitation of porcine spermatozoa. Sperm incubation in capacitating medium (CM) supplemented with 10 mM heparin for up to 120 min, showed an increase in the number of capacitated sperm (B pattern) and acrosome reacted sperm (AR pattern), without affecting their viability. In this condition, spermatozoa were incubated in CM depleted of albumin, calcium, bicarbonate or combinations, in the presence of heparin. In either calcium or bicarbonate-free media, capacitation was only basal and did not show variations in the presence of heparin. In absence of albumin the presence of calcium and bicarbonate stimulated capacitation, which was further increased by the addition of heparin. These results suggest that heparin enhances in vitro capacitation of porcine sperm only under capacitating conditions. Additionally, when sperm were incubated with 100 µg/ml biotinylated heparin in the presence or absence of unlabeled heparin, we observed that heparin binding sites were located mostly on the acrosomal region of boar sperm in an specific and saturable manner. The in vitro effect of heparin described in this work indicates that sulfated glycosaminoglycans, which are normally present in the female reproductive tract, might play an important role in the fertilization process in porcines.
Descritores: Heparina/farmacologia
Capacitação Espermática/efeitos dos fármacos
Espermatozoides/fisiologia
-Clortetraciclina
Corantes
Microscopia de Fluorescência
Sus scrofa
Limites: Animais
Masculino
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


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Id: lil-405203
Autor: Rosatti, M. I; Beconi, Martha T; Córdoba, M.
Título: Proacrosin-acrosin activity in capacitated and acrosome reacted sperm from cryopreserved bovine semen
Fonte: Biocell;28(3):311-316, dic. 2004. ilus, tab.
Idioma: en.
Resumo: Acrosin activity is associated with normal fertility in human and bovine spermatozoa. The aim of the study was to determine the variation of the enzyme activity in the proacrosin-acrosin system in capacitated and acrosome recated cryopreserved bovine sperm. Enzyme activity was assessed spectrophotometrically using N-alpha-benzoyl-DL-arginine p-nitroanilide (BAPNA) as specific substrate for acrosin at pH 8. Capacitation with heparin and quercitin failed to induce conversion of proacrosin to acrosin. An increase in acrosin activity produced by the presence of progesterone, in a dose-dependent manner, was related with the induction of true acrosome reaction. The total level of acrosin activity registered showed that 96 per cent of acrosin of capacitated sperm samples and control is present in the zymogen form. Moreover, progesterone is capable of duplicating the level of active enzyme, indicating that enzyme activity changes are related to acrosome reaction, suggesting that only a minor proportion of the total of proacrosin-acrosin system is required in the exocytotic process on cryopreserved bovine sperm.
Descritores: Acrosina/metabolismo
Capacitação Espermática/fisiologia
Espermatozoides
Precursores Enzimáticos/metabolismo
Quercetina/análogos & derivados
Quercetina/farmacologia
Reação Acrossômica/fisiologia
Sêmen/citologia
-Azul Tripano/química
Criopreservação
Clortetraciclina/química
Espermatozoides/enzimologia
Espermatozoides/fisiologia
Heparina/farmacologia
Microscopia de Fluorescência
Microscopia de Interferência
Progesterona/farmacologia
Limites: Bovinos
Animais
Responsável: AR1.1 - Biblioteca Rafael Herrera Vegas



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