Potassium transport in the maturing kidney.
The distal nephron and colon are the primary sites of regulation of potassium (K(+)) homeostasis, responsible for maintaining a zero balance in adults and net positive balance in growing infants and children. Distal nephron segments can either secrete or reabsorb K(+) depending on the metabolic needs of the organism. In the healthy adult kidney, K(+) secretion predominates over K(+) absorption. Baseline K(+) secretion occurs via the apical low-conductance secretory K(+) (SK) channel, whereas the maxi-K channel mediates flow-stimulated net urinary K(+) secretion. The K(+) retention characteristic of the neonatal kidney appears to be due not only to the absence of apical secretory K(+) channels in the distal nephron but also to a predominance of apical H-K-adenosine triphosphatase (ATPase), which presumably mediates K(+) absorption. Both luminal and peritubular factors regulate the balance between K(+) secretion and absorption. Perturbation in any of these factors can lead to K(+) imbalance. In turn, these factors may serve as effective targets for the treatment of both hyper-and hypokalemia. The purpose of this review is to present an overview of recent advances in our understanding of mechanisms of K(+) transport in the maturing kidney.
Gurkan
Sevgi
S
Department of Pediatrics, Division of Nephrology, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1664, New York, NY, 10029, USA.
Estilo
Genevieve K
GK
Wei
Yuan
Y
Satlin
Lisa M
LM
D000818:Animals; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D017506:H(+)-K(+)-Exchanging ATPase / Q000378:metabolism; D006801:Humans; D017136:Ion Transport / Q000502:physiology; D007668:Kidney / Q000254:growth & development / Q000378:metabolism*; D007685:Kidney Tubules, Collecting / Q000254:growth & development / Q000378:metabolism; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism; D008954:Models, Biological; D011188:Potassium / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism
D051036:Large-Conductance Calcium-Activated Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D048049:Extracellular Signal-Regulated MAP Kinases; D017506:H(+)-K(+)-Exchanging ATPase; D011188:Potassium