RESUMO
Human fetal red cells show heterogeneity of 3H-ouabain binding sites. These cells were chosen as a model to look into unconjugated bilirubin effects on the primary active Na(+)-K+ transport mechanism. Evidences are presented suggesting that unconjugated bilirubin affects 3H-ouabain binding but not through a direct effect. This is supported by the fact that the "low affinity" subgroup sites of the last mentioned ligand persists after unconjugated bilirubin treatment of cells, whereas the "high-affinity" subgroup disappears.
Assuntos
Bilirrubina/farmacologia , Eritrócitos/efeitos dos fármacos , Sangue Fetal/citologia , Ouabaína/metabolismo , ATPase Trocadora de Sódio-Potássio/sangue , Sítios de Ligação , Membrana Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/metabolismo , Humanos , Ligantes , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidoresRESUMO
Human neonatal red cells (placental blood) incubated in hypertonic sucrose media showed a significative lytic process in a relatively short time interval. The addition of sodium chloride into the sucrose media reduced the extent of hemolysis. In contrast, the addition of calcium chloride enhanced the hemolysis in these red cells. Calcium-membrane components complex formation that destabilize membrane's bilayer structure would explain the calcium effect above mentioned (on account of the low ionic strength media used and exposed fixed negative charges) This study intends to clarify, in neonatal red cells, the relation between surface charges and cellular stability.