Biomaterial Database

PAH transport and fluid absorption by isolated perfused frog proximal renal tubules. 1976

J M Irish, and W H Dantzler

Para-aminohippurate (PAH) transport and fluid absorption were studied in isolated perfused frog (Rana catesbeiana) proximal renal tubules. With 2 X 10(-5) M PAH in the bath, tubule fluid-to-bath (TF/B) concentration ratios averaged 3.0 and net secretion averaged 746 X 10(-15) mol min(-1) mm(-1) in the proximal tubule. Net PAH secretion did not vary with perfusion rate. During PAH secretion, cell water PAH concentration exceeded that in the tubular fluid or bath, suggesting active transport into cells and subsequent diffusion into lumen. In accordance with this concept, luminal membrane permeability (3.8 X 10(-5) cm s(-1) calculated from perfusion studies was about 6 times greater than peritubular membrane permeability (0.66 X 10(-5) cm s(-1)) determined from studies of PAH efflux from tubules with oil-filled lumens. Net transepithelial PAH transport saturated at bath concentration of about 6 X 10(-5) M. Addition of 20 mM urea to PAH bath concentration of 2 X 10(-5) M reduced net PAH secretion by 32%. Fluid absorption in proximal tubules averaged 0.34 nl min(-1) mm(-1). Ouabain (10(-4), 10(-5), or 10(-6) M) added to bath blocked fluid absorption. Fluid absorption was partially restored following removal of ouabain.

UI	MeSH Term	Description	Entries
D007687	Kidney Tubules, Proximal	The renal tubule portion that extends from the BOWMAN CAPSULE in the KIDNEY CORTEX into the KIDNEY MEDULLA. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the U-shaped LOOP OF HENLE.	Proximal Kidney Tubule,Proximal Renal Tubule,Kidney Tubule, Proximal,Proximal Kidney Tubules,Proximal Renal Tubules,Renal Tubule, Proximal,Renal Tubules, Proximal,Tubule, Proximal Kidney,Tubule, Proximal Renal,Tubules, Proximal Kidney,Tubules, Proximal Renal
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D010042	Ouabain	A cardioactive glycoside consisting of rhamnose and ouabagenin, obtained from the seeds of Strophanthus gratus and other plants of the Apocynaceae; used like DIGITALIS. It is commonly used in cell biological studies as an inhibitor of the NA(+)-K(+)-EXCHANGING ATPASE.	Acocantherin,G-Strophanthin,Acolongifloroside K,G Strophanthin
D010539	Permeability	Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.	Permeabilities
D005260	Female		Females
D000085	Acetates	Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.	Acetate,Acetic Acid Esters,Acetic Acids,Acids, Acetic,Esters, Acetic Acid
D000618	Aminohippuric Acids	A group of glycine amides of aminobenzoic acids.	Acids, Aminohippuric
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001693	Biological Transport, Active	The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.	Active Transport,Uphill Transport,Active Biological Transport,Biologic Transport, Active,Transport, Active Biological,Active Biologic Transport,Transport, Active,Transport, Active Biologic,Transport, Uphill