Gut sensing of dietary K+ intake increases renal K+ excretion

초록

Oh K, Oh YT, Kim S, Kita T, Kang I, Youn JH. Gut sensing of dietary K+ intake increases renal K+ excretion. Am J Physiol Regul Integr Comp Physiol 301: R421-R429, 2011. First published May 4, 2011; doi:10.1152/ajpregu.00095.2011.-Dietary K+ intake may increase renal K+ excretion via increasing plasma [K+] and/or activating a mechanism independent of plasma [K+]. We evaluated these mechanisms during normal dietary K+ intake. After an overnight fast, [K+] and renal K+ excretion were measured in rats fed either 0% K+ or the normal 1% K+ diet. In a third group, rats were fed with the 0% K+ diet, and KCl was infused to match plasma [K+] profile to that of the 1% K+ diet group. The 1% K+ feeding significantly increased renal K+ excretion, associated with slight increases in plasma [K+], whereas the 0% K+ diet decreased K+ excretion, associated with decreases in plasma [K+]. In the KCl-infused 0% K+ diet group, renal K+ excretion was significantly less than that of the 1% K+ group, despite matched plasma [K+] profiles. We also examined whether dietary K+ alters plasma profiles of gut peptides, such as guanylin, uroguanylin, glucagon-like peptide 1, and glucose-dependent insulinotropic polypeptide, pituitary peptides, such as AVP, alpha-MSH, and alpha-MSH, or aldosterone. Our data do not support a role for these hormones in the stimulation of renal K+ excretion during normal K+ intake. In conclusion, postprandial increases in renal K+ excretion cannot be fully accounted for by changes in plasma [K+] and that gut sensing of dietary K+ is an important component of the regulation of renal K+ excretion. Our studies on gut and pituitary peptide hormones suggest that there may be previously unknown humoral factors that stimulate renal K+ excretion during dietary K+ intake.

키워드