title: Primary defect of juvenile visceral steatosis (jvs) mouse with systemic carnitine deficiency is probably in renal carnitine transport system.
abstract: We investigated the reabsorptional system for carnitine in the kidney to elucidate the mechanism of carnitine deficiency in juvenile visceral steatosis (jvs) mice. Jvs mice had a higher rate of carnitine excretion at 10 days after birth than the controls, in spite of having no pathological acylcarnitine excretion in the urine. In an experiment to assay the uptake of carnitine using kidney slices, homozygous mutants showed significantly lower rates of Na-dependent carnitine uptake than controls. Heterozygous mice showed values of transport activity intermediate between homozygous mutants and homozygous controls. Scatchard plots (transport activity versus transport activity/carnitine concentration) revealed that the homozygous mutants had a defect in the high affinity site (Km = 58 microM) in the Na-dependent carnitine transport system in the kidney. These results indicate that the primary defect of jvs mice is most probably related to the system for reabsorption of carnitine in the kidney.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Kagoshima University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Horiuchi
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.forename: S
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: N
authors.initials: N
authors.lastname: Shimizu
authors.forename: T
authors.initials: T
authors.lastname: Koizumi
authors.forename: H
authors.initials: H
authors.lastname: Nikaido
authors.forename: J
authors.initials: J
authors.lastname: Hayakawa
authors.forename: M
authors.initials: M
authors.lastname: Kuwajima
authors.forename: T
authors.initials: T
authors.lastname: Saheki
mesh_terms: D000042:Absorption; D000818:Animals; D001692:Biological Transport; D002331:Carnitine / Q000172:deficiency / Q000378:metabolism*; D005260:Female; D006579:Heterozygote; D006720:Homozygote; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism*; D007700:Kinetics; D008052:Lipid Metabolism, Inborn Errors / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008817:Mice, Mutant Strains; D012964:Sodium / Q000494:pharmacology
chemical_list: D012964:Sodium; D002331:Carnitine