fifteen g daily regarding slimming down K + intake sustained for 20 days (20, 43). Current results (talked about lower than) features identified the clear presence of a keen enteric K + feeling system one starts the brand new renal secretory process upon K + entry for the digestion. New distal convoluted tubule could have been recognized as an internet site important to own K + homeostasis, where they will act as a K + alarm with the capacity of unveiling K + excretion independent away from mineralocorticoid craft.
Article on Renal K + Addressing
K + was easily blocked along the glomerulus then avidly reabsorbed by the new proximal tubule and you will dense rising limb of renal. K + reabsorption about proximal tubule is especially through the paracellular path that will be inside rough proportion towards the number of Na + and you can liquid reabsorbed (Fig. 1). About dense ascending limb, K + reabsorption happen by the one another transcellular and you can paracellular pathways. Transcellular path is mediated of the Na + -K + -2Cl ? cotransporter found on the apical membrane layer. Some K + that goes into the cell right back diffuses with the lumen through the ROMK (kidney is datehookup free outside medullary K + ) station, resulting in the fresh new age group off an excellent lumen positive fees which, subsequently, pushes an element of K + reabsorption through the paracellular path (Fig. 2). K + secretion begins inside the very early distal convoluted tubule and you may increasingly expands in magnitude into the cortical event duct. Emotional demands handle this new secretory component of K + addressing (36).
Fig. step one.A huge element of blocked K + is actually reabsorbed because of the proximal tubule mostly from paracellular path passionate by the solvent pull. The fresh new change in lumen potential away from bad so you can positive in the after servings of your proximal tubule will bring an extra driving force to possess K + reabsorption. On basolateral skin, K + admission into intracellular room because of the Na + -K + -ATPase exits coupled so you’re able to Cl ? through a beneficial conductive path. An excellent K + station on the apical skin of your own proximal tubule serves so you’re able to balance out phone voltage given the depolarizing effect of Na + -coupled glucose and you may amino acid reabsorption.
Fig. 2.Most blocked K + one to escapes reabsorption in the proximal tubule is actually reabsorbed in the thick rising limb because of the one another trancellular and paracellular paths. The brand new trancellular path was an example of additional productive transport. Intracellular Na + was kept lowest by the pastime of your Na + -K + -ATPase. Luminal Na + enters the brand new mobile as well as Cl ? and you may K + via the Na + -K + -Cl ? cotransporter. An adequate amount of luminal K + on the cotransport action are made certain from the K + path in the intracellular space for the lumen through the apically discover renal outside medullary potassium (ROMK) station. This recycling from K + contributes to age bracket regarding a beneficial lumen-confident charges, providing the power to possess a second component of K + reabsorption from the paracellular pathway. Intracellular K + may also leave the newest basolateral membrane in the cotransport which have Cl ? or as a result of a beneficial conductive path. ClC-Kb, Cl ? route.
Maxi-K + or BK avenues is actually a second variety of channel that also mediates K + hormonal not as much as requirements from improved move
Electrogenic secretion from the ROMK station ‘s the major K + secretory mechanism from the distal nephron. As well as exciting maxi-K + channels, tubular circulate including augments electrogenic K + hormonal from the diluting luminal K + amount and you may exciting Na + reabsorption from the epithelial Na + station (ENaC). Which stimulatory feeling is traced to help you a mechanosensitive assets in which shear stress increases the open odds of the newest ENaC route (30).
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