Adenosine and hypoxanthine transport in horse erythrocytes: evidence for a polymorphism in the transport of hypoxanthine via a sodium-dependent cotransporter.
Exp Physiol
; 83(2): 203-9, 1998 Mar.
Article
em En
| MEDLINE
| ID: mdl-9568480
ABSTRACT
The inward transport of two purines, adenosine and hypoxanthine, at 37 degrees C by horse erythrocytes was compared. No mediated transport of adenosine was detected in horse erythrocytes, nor was saturable, high-affinity binding of the potent facilitated-diffusion inhibitor nitrobenzylthioinosine demonstrable in horse erythrocyte membranes. In contrast, erythrocytes from most horses possessed a saturable sodium-dependent hypoxanthine transporter (apparent K(m), 100 +/- 28 microM; Vmax, 0.20 +/- 0.08 mmol (l cells)-1 h-1; means +/- S.E.M., n = 5). Guanine inhibited hypoxanthine influx (apparent Ki, 24 +/- 6 microM), but adenine and xanthine had no effect. Unlike human erythrocytes, no sodium-independent hypoxanthine transporter was detected in horse erythrocytes. There are, however, a small number of animals (approximately 15%) whose erythrocytes fail to transport hypoxanthine. This variation appears to be under genetic control, but the precise nature of the control is unknown.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Membrana Transportadoras
/
Adenosina
/
Hipoxantina
/
Eritrócitos
Limite:
Animals
Idioma:
En
Revista:
Exp Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Reino Unido