RESUMEN
Tyrosine nitration is a widely used marker of peroxynitrite (ONOO-) produced from the reaction of nitric oxide (NO.) with superoxide (O2(.-)). Since human spermatozoa are able to produce both NO. and O2(.-) during capacitation in vitro, we investigated whether spontaneous tyrosine nitration of proteins occurs in human spermatozoa and evaluated the physiological effects of peroxynitrite on sperm function. We report here that human spermatozoa, incubated for 8 h under conditions conducive to capacitation, display a reproducible pattern of protein tyrosine nitration. Several proteins with mol. wt of 105-14 kDa become increasingly tyrosine-nitrated after 15 min incubation and then minimal changes are observed. Treatment of capacitated spermatozoa with human follicular fluid or calcium ionophore causes an increase of the nitrotyrosine content of proteins at the mol. wt of 85 kDa. Moreover, exposure of spermatozoa to ONOO- (2.5-50 micromol/l) increases motility and primes spermatozoa to respond earlier to human follicular fluid. ONOO- also increases protein tyrosine nitration and phosphorylation in a concentration-dependent manner. Taken together, these results demonstrate that tyrosine nitration of sperm proteins occurs in capacitated human spermatozoa, and that low concentrations of ONOO- modulate sperm functions, emphasizing the concept that capacitation is part of an oxidative process.
Asunto(s)
Óxido Nítrico/metabolismo , Ácido Peroxinitroso/fisiología , Espermatozoides/metabolismo , Superóxidos/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismo , Calcimicina/farmacología , Femenino , Líquido Folicular , Humanos , Ionóforos/farmacología , Masculino , Óxido Nítrico/química , Ácido Peroxinitroso/farmacología , Fosforilación , Proteínas/metabolismo , Capacitación Espermática/efectos de los fármacos , Capacitación Espermática/fisiología , Motilidad Espermática/efectos de los fármacos , Espermatozoides/efectos de los fármacosAsunto(s)
Agammaglobulinemia/complicaciones , Estatura/efectos de los fármacos , Trastornos del Crecimiento/complicaciones , Trastornos del Crecimiento/diagnóstico , Hormona de Crecimiento Humana/deficiencia , Hormona de Crecimiento Humana/uso terapéutico , Trastornos del Sueño-Vigilia/complicaciones , Agammaglobulinemia/diagnóstico , Agammaglobulinemia/inmunología , Preescolar , Femenino , Trastornos del Crecimiento/tratamiento farmacológico , Humanos , SíndromeRESUMEN
Fetal hemoglobin (HbF) synthesis in children with congenital cyanotic heart disease was compared that in normal children. Children with hypoxemia had higher levels of hemoglobin, total HbF, and HbF synthesis. In these children there was also an inverse correlation between HbF synthesis and oxygen content, as well as between HbF synthesis and hemoglobin concentration. Thus hypoxemia increases HbF synthesis.