Intercalated duct

Primary saliva is modified in the intercalated, striated, and excretory (collecting) ducts that lead from the acini to the mouth. Water and electrolyte transport into the saliva is beUeved to occur in the intercalated ducts. Striated ducts are responsible for electrolyte transport such as secretion of potassium and reabsorption of sodium ions. A transport of proteins Like IgA, lysozyme, and kallikrein [and may be Hsp70 (2)] probably exists in the striated duct as well. An electrolyte transport in the excretory (collecting) ducts is also suspected (1). 

Donath K, Seifert G, Schmitz R. [Diagnosis and ultrastructure of the tubular carcinoma of salivary gland ducts. Epithelial-myoepithelial carcinoma of the intercalated ducts]. Yirch Arch A Pathol Pathologische Anat. 1972 356(1) 16-31. 

In the pancreas and ampulla, the glandular/ductal system is characterized and distinguished by mucin production. With the exception of centroacinar cells/intercalated ducts in the pancreas and the serous cystadenomas that presumably recapitulate this earliest component of the ductal system, virtually all glandular elements... 

Instead, it commonly expresses the markers of centroacinar-cell/intercalated duct system such as MUC6, as well as markers of clear cell tumorigenesis such as GLUT-1, HIL-la, and carbonic anhydrase IX. 

AQP6 is expressed in the intercalated cells of the kidney collecting duct. This channel is hardly permeable to water, but capable of transporting anions, including chloride, and is therefore thought to play a role in maintenance of body acid-base balance or in intracellular vesicle acidification. 

Principal and intercalated cells of the collecting ducts. Principal (top) cells reabsorb Na+ and the secreted K+. Na+ entry across apical cell membranes is mediated by a Na+ channel. Na+ exit across basolateral cell membranes is effected by the NaVK+-ATPase, shown by the filled circle in the principal cell. The rates of Na+ reabsorption and K+ secretion are regulated by aldosterone. Intercalated (bottom) cells reabsorb K+ and HCOa and secretes H+. K+ entry and H+secretion are mediated by an H+/K ATPase, which is shown by the filled circle in the apical cell membrane of the intercalated cell. 

Brown, D., Weyer, P. and Orci, L. (1987). Nonclathrin-coated vesicles are involved in endocytosis in kidney collecting duct intercalated cells. Anat. Rec. 218, 237-242. 

The principal and intercalated cells of the collecting tubule aie responsible for Na+- K+ exchange and for H+ secretion and K+ reabsorption, respectively. Stimulation of aldosterone receptors in the principal cells results in Na+ reabsorption and K+ secretion. Antidiuretic hormone (ADH, vasopressin) receptors promote the reabsorption of water from the collecting tubules and ducts (Figure 23.3). This action is mediated by cAMP. 

Interleukin-18 (IL-18), a recently described member of the IL-1 cytokine family, is now recognized as an important regulator of innate and acquired immune responses. IL-18 is a mediator of inflammation and ischemic tissue injury in many organs. IL-18 is con-stitutively expressed by intercalated cells of the late distal convoluted tubule, fhe connecting tubule, and the collecting duct of the healthy human kidney [229]. It is expressed at sites of chronic inflammation, in autoimmune diseases, in a variety of cancers, and in the... 

CD-IC collecting duct intercalated cell DICE difference in-gel electrophoresis... 

Ultrastructural and immunohistochemical features of ChromRCC point to differentiation toward the intercalated cells of renal collecting ducts (Table 16.15). 1 3,358-360,362,383,384,394,410-416... 

DCT=distal convoluted tubule cell CD-PC=collecting duct principal cell CD-IC=collecting duct intercalated cell. 

Pendrin is expressed in type B intercalated cells in the renal collecting duct and involved in chloride/bicarbo-nate exchange. Pendrin knockout mice have a decreased rise in blood pressure in response to a high salt diet or treatment with aldosterone analogs. 

The two subunits of the ATPase are synthesized In the ER of the parietal cell. The only other location of the pump Is In the Intercalated cells of the collecting duct of the kidney. Formation of transmembrane segments requires Interaction of hydrophobic sequences during translation with the Interior surface of the translocon. A sequence that determines membrane Insertion with Its N-termlnal cytoplasmic and C-termlnal extracytoplasmic Is termed a s/gna/ anchor sequence. A sequence that returns the translating protein back to the cytoplasm and, thus, with Its N-termlnal extracytoplasmic, Is named a stop transfer sequence. 

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