title: Transepithelial endoplasmic reticulum in rat proximal convoluted tubule.
abstract: Inosine 5'-diphosphatase (IDPase) activity was demonstrated cytochemically in the endoplasmic reticulum of rat kidney proximal tubule cells in tissue fixed by perfusion with glutaraldehyde--formaldehyde. Incubation for IDPase activity at pH 7.2 was performed with and without 0.5 mM levamisole, a potent inhibitor of alkaline phosphatase (AlkPase) (M Borgers, J Histochem Cytochem 21:812, 1973). Levamisole treatment of sections eliminated all reaction product in the brush border, but did not affect the IDPase activity the endoplasmic reticulum (ER). The ER appears as a basilar-luminal-oriented transcellular structure, suggesting a possible cellular transport route. This study supports and extends earlier observations made by others that suggest a transport role for the ER in these cells. It also emphasizes the value of thick section cytochemistry.
mesh_terms: D017766:Acid Anhydride Hydrolases; D000818:Animals; D002465:Cell Movement; D004721:Endoplasmic Reticulum / Q000201:enzymology*; D006651:Histocytochemistry; D007687:Kidney Tubules, Proximal / Q000033:anatomy & histology / Q000648:ultrastructure*; D007978:Levamisole / Q000494:pharmacology; D008297:Male; D008871:Microvilli / Q000033:anatomy & histology; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007978:Levamisole; D010744:Phosphoric Monoester Hydrolases; D017766:Acid Anhydride Hydrolases; C021446:inosine diphosphatase