Renal potassium handling in healthy and sick newborns.
Growing infants must maintain a state of positive K+ balance, a task accomplished, in large part, by the kidney. The distal nephron is uniquely adapted to retain total body K+ early in life. The magnitude and direction of net K+ transport in the cortical collecting duct (CCD), the segment responsible for the final renal regulation of K+ balance in the adult, reflect the balance of opposing fluxes of K+ secretion and K+ absorption. Evidence now indicates that the low capacity of the neonatal CCD for K+ secretion is due, at least in part, to a relative paucity of conducting K+ channels in the urinary membrane. A relative excess of K+ absorption in this nephron segment may further reduce net urinary K+ secretion. Under conditions prevailing in vivo, the balance of fluxes in the CCD likely contributes to the relative K+ retention characteristic of the neonatal kidney.
Zhou
Hao
H
Division of Neonatology, Department of Pediatrics, Mount Sinai School of Medicine, New York, NY 10029, USA.
Satlin
Lisa M
LM
D000042:Absorption; D001692:Biological Transport; D005260:Female; D006304:Health Status; D006706:Homeostasis; D006801:Humans; D007231:Infant, Newborn; D007668:Kidney / Q000254:growth & development* / Q000378:metabolism*; D007685:Kidney Tubules, Collecting / Q000254:growth & development / Q000378:metabolism; D008297:Male; D011188:Potassium / Q000008:administration & dosage / Q000378:metabolism*; D015221:Potassium Channels; D012964:Sodium / Q000378:metabolism
D015221:Potassium Channels; D012964:Sodium; D011188:Potassium