part of part of epithelial cell of proximal tubule kidney outer medulla cell kidney proximal straight tubule epithelial cell https://cellxgene.cziscience.com/cellguide/CL_1000839 Kidney proximal straight tubule epithelial cells line the straight portion of the proximal tubule of the nephron, extending from the cortical medullary ray into the outer stripe of the outer medulla. They are characterized by a brush border of dense microvilli on their apical surface, enhancing the cell's surface area and aiding reabsorption, though reabsorption occurs more heavily in the proximal convoluted tubule preceding the straight portion of the tubule. The primary function of the kidney proximal straight tubule epithelial cells is to reabsorb the filtrate that the kidney produces, which includes glucose, sodium, and water. The reabsorption occurs through both passive and active transport methods. These cells exhibit enzyme-rich microvilli that also absorb small proteins and peptides. Consequently, they are involved in the regulation of plasma levels of various substances, including glucose, amino acids, and electrolytes, and maintain the body's pH homeostasis by secreting H+ ions into the urine and absorbing bicarbonate ions. These cells are also reported to be involved in drug metabolism. Many drugs are filtered from the blood by the kidneys and subsequently reabsorbed by the kidney proximal tubule epithelial cells back into the bloodstream. Furthermore, these cells play a significant role in the progression of kidney diseases. For example, in diabetic nephropathy and acute kidney injury, kidney proximal straight tubule epithelial cells can undergo cellular changes and result in malfunctions such as reduced reabsorption and increased excretion. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) Any epithelial cell of proximal tubule that is part of some proximal straight tubule. KUPO:0001046 kidney loop of Henle descending limb epithelial cell proximal straight tubule