fifteen g day-after-day out-of fat reduction K + consumption sustained to possess 20 days (20, 43). Recent conclusions (chatted about below) has known the clear presence of an enteric K + feeling system you to definitely starts the latest kidney secretory techniques on K + admission to the digestion. The fresh distal convoluted tubule has been recognized as a web site vital getting K + homeostasis, where they will act as an effective K + detector effective at releasing K + excretion separate away from mineralocorticoid pastime.
Breakdown of Kidney K + Handling
K + was easily blocked along the glomerulus after which avidly reabsorbed from the the proximal tubule and you can thicker ascending limb of the renal. K + reabsorption throughout the proximal tubule is principally from the paracellular path in fact it is inside harsh proportion into level of Na + and water reabsorbed (Fig. 1). Regarding thicker rising limb, K + reabsorption happen of the both transcellular and you may paracellular routes. Transcellular way is actually mediated of the Na + -K + -2Cl ? cotransporter on the apical membrane layer. An element of K + you to gets in the new telephone back diffuses with the lumen from the ROMK (kidney exterior medullary K + ) channel, leading to brand new age group regarding a beneficial lumen positive fees and this, therefore, pushes some K + reabsorption through the paracellular path (Fig. 2). K + secretion starts when you look at the very early distal convoluted tubule and progressively develops during the magnitude with the cortical event duct. Emotional requires regulate new secretory part of K + approaching (36).
Fig. step 1.A giant component of filtered K + is actually reabsorbed of the proximal tubule generally through the paracellular path passionate by solvent drag. The fresh new change when you look at the lumen possible regarding negative so you can confident on later servings of your own proximal tubule will bring a supplementary driving force to have K + reabsorption. To the basolateral epidermis, K + admission toward intracellular space by Na + -K + -ATPase exits combined so you can Cl ? through a great conductive path. A great K + route into apical facial skin of proximal tubule acts so you can stabilize cell current given the depolarizing aftereffect of Na + -coupled glucose and you will amino acidic reabsorption.
Fig. dos.More filtered K + you to escapes reabsorption regarding the proximal tubule is actually reabsorbed throughout the heavy ascending limb of the both trancellular and you may paracellular routes. Brand new trancellular path is a good example of secondary effective transport. Intracellular Na + is leftover lowest by hobby of Na + -K + -ATPase. Luminal Na + goes into the new cell and Cl ? and K + via the Na + -K + -Cl ? cotransporter. Enough of luminal K + into cotransport step are made sure by the K + way throughout the intracellular space to your lumen through the apically located kidney external medullary potassium (ROMK) channel. That it recycling out-of indiancupid K + contributes to generation regarding an effective lumen-self-confident charge, providing the power to have the second element of K + reabsorption from paracellular pathway. Intracellular K + may exit new basolateral membrane when you look at the cotransport with Cl ? or thanks to a conductive pathway. ClC-Kb, Cl ? channel.
Maxi-K + or BK avenues try the second particular station that can mediates K + hormonal less than conditions away from enhanced move
Electrogenic secretion from ROMK route is the big K + secretory method on distal nephron. Also revitalizing maxi-K + streams, tubular flow including augments electrogenic K + hormonal of the diluting luminal K + focus and you will revitalizing Na + reabsorption from epithelial Na + channel (ENaC). This stimulatory impact are traced to help you a mechanosensitive assets by which shear stress boosts the discover likelihood of the fresh new ENaC route (30).
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