Insulin affects the sodium affinity of the rat adipocyte (Na ,K )-ATPase

Journal Article · Sun Aug 25 04:00:00 EDT 1985 · J. Biol. Chem.; (United States)

OSTI ID:6335893

Lytton, J

The K0.5 for intracellular sodium of the two forms of (Na ,K )-ATPase which exist in rat adipocytes has been determined by incubating the cells in the absence of potassium in buffers of varying sodium concentration; these conditions shut off the Na pump and allow sodium to equilibrate into the cell. The activity of (Na ,K )-ATPase was then monitored with YWRb /K pumping which was initiated by adding isotope and KCl to 5 mM, followed by a 3-min uptake period. Atomic absorption and SSNa tracer equilibration were used to determine the actual intracellular (Na ) under the different conditions. The K0.5 values thus obtained were 17 mM for alpha and 52 mM for alpha(+). Insulin treatment of rat adipocytes had no effect on the intracellular (Na+) nor on the Vmax of YWRb /K pumping, but did produce a shift in the sodium ion K0.5 values to 14 mM for alpha and 33 mM for alpha(+). This change in affinity can explain the selective stimulation of alpha(+) by insulin under normal incubation conditions.

• Research Organization: Harvard Univ., Cambridge, MA
• OSTI ID: 6335893
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 18; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ADIPOSE TISSUE
ALKALI METAL ISOTOPES
AMIDES
ANIMAL TISSUES
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BIOLOGICAL EFFECTS
BODY
CARBONIC ACID DERIVATIVES
CHEMISTRY
CONNECTIVE TISSUE
DAYS LIVING RADIOISOTOPES
ENZYMES
EXTRACELLULAR SPACE
HORMONES
HYDROLASES
INSULIN
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
MEMBRANE TRANSPORT
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDE HORMONES
PHOSPHOHYDROLASES
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
RUBIDIUM 86
RUBIDIUM ISOTOPES
SODIUM 22
SODIUM ISOTOPES
SPACE
TISSUES
TRITIUM COMPOUNDS
UREA
VERTEBRATES
YEARS LIVING RADIOISOTOPES