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| Untersuchte Arbeit: Seite: 38, Zeilen: 1-16 |
Quelle: Boini 2006 Seite(n): 20, 21, Zeilen: 20: 18ff; 21: 1ff |
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| Patch-clamp studies on rat CCDs found no measurable effect of acute aldosterone administration on K+ channel number, open probability, or conductance (Palmer LG. et al., (1994) Am J Physiol). However, some data suggested that aldosterone induces renal K+ secretion already at aldosterone concentrations that do not exhibit any measurable effect on urinary Na+ excretion (Bhargava et al., (2001) Endocrinology). Moreover, high K+ intake increases ROMK activity more efficiently in intact rats than in adrenalectomized animals, suggesting that aldosterone may have at least a permissive effect on ROMK activation (Palmer LG. et al., (1994) Am J Physiol).
Consistent with a possible role of aldosterone in ROMK regulation, recent studies in heterologous expression systems advocated a regulatory action of aldosterone-induced SGK1 on ROMK cell surface activity and abundance (Palmada M. et al., (2003) Biochem Biophys Res Commun). The regulatory role of SGK1 with regard to ROMK may be indirect via increased interaction with the Na+, H+ exchanger–regulating factor 2 (NHERF2) (Palmada M. et al., (2003) Biochem Biophys Res Commun) or direct via increased phosphorylation of ROMK at a serine residue within the canonical SGK1 consensus phosphorylation motif (Yoo D. et al., (2003) J Biol Chem). |
Patch-clamp studies on rat CCDs found no measurable effect of acute aldosterone administration on K+ channel number, open probability, or conductance (Palmer et al., 1994). However, some data suggested that aldosterone induces renal K+ secretion already at aldosterone concentrations that do not exhibit any measurable effect on urinary Na+ excretion (Bhargava et al., 2001). Moreover, high K+ intake increases ROMK activity more efficiently in intact rats than in adrenalectomized animals, suggesting that aldosterone may have at least a permissive effect on ROMK activation (Palmer et al., 1994). Consistent with a possible role of aldosterone in ROMK regulation, recent studies in heterologous expression systems advocated a regulatory action of aldosterone-induced SGK1 on ROMK cell surface activity and abundance (Palmada et al., 2003, Palmada et al., 2003a). The regulatory role of SGK1 with regard to ROMK may be indirect via increased interaction with the Na+, H+ exchanger–regulating factor 2 (NHERF2) (Palmada et al., 2003, Palmada et al., 2003a) or direct via
[page 21] increased phosphorylation of ROMK at a serine residue within the canonical SGK1 consensus phosphorylation motif (Yoo et al., 2003). |
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