Radiation target sizes of the Na,K-ATPase and p-aminohippurate transport system in the basolateral membrane of renal proximal tubule.
Basolateral membrane vesicles made from rabbit kidney proximal tubules were frozen and irradiated with a high energy electron beam and the effects of irradiation on Na,K-ATPase activity, p-aminohippurate (PAH) transport, the membrane diffusion barrier and vesicle volume were measured. The vesicle volume and diffusion barrier were not significantly changed by radiation exposure. Na,K-ATPase activity was inactivated as a simple exponential function of radiation dose. Target size analysis of the data yielded a molecular size of 267 +/- 17 kDa, consistent with its existence as a (alpha beta)2 dimer. The carrier-mediated PAH uptake by basolateral membrane vesicles was also inactivated as a function of radiation dose. A target molecular size of 74 +/- 16 kDa was calculated for the PAH transport system. This study is the first measurement of the functional size of the organic acid transport system based directly on flux measurements.
Kwon
H M
HM
Department of Physiology, State University of New York, Buffalo.
D000618:Aminohippuric Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D015415:Biomarkers; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D002463:Cell Membrane Permeability; D004789:Enzyme Activation; D005947:Glucose / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D011339:Probenecid / Q000494:pharmacology; D011487:Protein Conformation; D011817:Rabbits; D015203:Reproducibility of Results; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D010130:p-Aminohippuric Acid / Q000378:metabolism*
D000618:Aminohippuric Acids; D015415:Biomarkers; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D005947:Glucose; D011339:Probenecid; D010130:p-Aminohippuric Acid