most sodium is reabsorbed in the kidney through the proximal tubule.
most sodium is reabsorbed in the kidney through the proximal tubule.
where is most sodium reabsorbed in the kidney?
the proximal tubule
it was originally thought that diabetes mellitus was a renal disorder because of the glucose found in the urine. once insulin was discovered the focus of diabetes management was on the pancreas. traditional focuses of therapeutic strategies for diabetes have been to enhance endogenous insulin secretion and to improve insulin sensitivity. in the previous decade the role of the kidney in the development and maintenance of high glucose levels has been examined. the role of the kidney led to the development of drugs that inhibit the sodium/glucose transporter 2 protein. every day approximately 180 grams of glucose are filtered through the glomeruli and lost into the primary urine in healthy adults, but more than 90% of the glucose that is initially filtered is reabsorbed by a high capacity system controlled by sglt-2 in the early convoluted segment of the proximal tubules. almost all remaining filtered glucose is reabsorbed by sodium/glucose transporter 1 so under normal circumstances almost all filtered glucose will be reabsorbed and less than 100 mg of glucose finds its way into the urine of non-diabetic individuals.
discovery and development of gliflozins
the thick ascending limb of the loop of henle begins at the deeper portion of the renal outer medulla. here, the urine has a relatively high concentration of sodium. as urine moves towards the more superficial portion of the thick ascending limb, nkcc2 is the major transport protein by which sodium is reabsorbed from the urine. this outward movement of sodium and the lack of water permeability in the thick ascending limb, creates a more diluted urine. according to the stoichiometry outlined above, each molecule of sodium reabsorbed brings one molecule of potassium and two molecules of chloride. sodium goes on to be reabsorbed into the blood, where it contributes to the maintenance of blood pressure.
na-k-cl cotransporter