Cystinuria in dogs: comparison of the cystinuric component of the Fanconi syndrome in basenji dogs to isolated cystinuria.
Two animal models for cystinuria have been examined: the Basenji dog with Fanconi syndrome and cystine stone-forming dogs of various breeds. Brush-border membranes were isolated from these animals and uptake of D-glucose and L-cystine was characterized. Experiments with isolated brush-border vesicles from Basenji dogs with cystinuria as a component of the Fanconi syndrome showed diminished sodium-dependent D-glucose uptake but no decrease in L-cystine uptake even though the cystine defect in vivo was as high as 94% (ie, 6% reabsorption). In contrast, brush-border vesicles isolated from the kidney of a cystine stone-forming dog (Welsh Corgi) with a cystine defect of only 16% (ie, 84% reabsorption) had decreased uptake of cystine compared to values found for Beagle and Basenji vesicles. Thus, cystinuria found in Basenji dogs with the Fanconi syndrome differs from that in classic stone-forming cystinuric dogs. The alteration responsible for the cystinuria of Basenji dogs with Fanconi syndrome does not appear to have a membrane locus and may reflect altered energetics for transport, which are not detected in isolated vesicles. The cystine defect in cystinuric stone-forming dogs does appear to be reflected in the isolated membrane.
McNamara
P D
PD
Division of Biochemical Development and Molecular Diseases, Children's Hospital, Philadelphia, PA.
Rea
C T
CT
Bovee
K C
KC
Reynolds
R A
RA
Segal
S
S
D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport; D003553:Cystine / Q000378:metabolism; D003555:Cystinuria / Q000378:metabolism*; D004195:Disease Models, Animal; D004285:Dogs; D005198:Fanconi Syndrome / Q000378:metabolism*; D005260:Female; D005919:Glomerular Filtration Rate; D005947:Glucose / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008871:Microvilli / Q000378:metabolism; D012964:Sodium / Q000494:pharmacology
D000596:Amino Acids; D003553:Cystine; D012964:Sodium; D005947:Glucose