Abstract
Astroglia-rich cultures derived from brains of newborn rats or mice use a transport system for the uptake of creatine. The uptake system is saturable, Na+-dependent, and highly specific for creatine and Na+. Kinetic studies on rat cells revealed a Km value for creatine of 45 microM, a Vmax of 17 nmol x h-1 x (mg of protein)-1, and a Km value of 55 mM for Na+. The carrier is competitively inhibited by guanidinopropionate (Ki = 15 microM). No such transport system was found in neuron-rich primary cultures from embryonic rat brain. It is hypothesized that creatine transport is an astroglial rather than a neuronal function.
Publication types
-
Comparative Study
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
Astrocytes / metabolism*
-
Binding, Competitive
-
Biological Transport / drug effects
-
Brain / metabolism*
-
Carrier Proteins / metabolism
-
Cells, Cultured
-
Creatinine / metabolism*
-
Glioma
-
Guanidines / pharmacology
-
Kinetics
-
Mice
-
Neuroblastoma
-
Neurons / metabolism
-
Ouabain / pharmacology
-
Propionates / pharmacology
-
Rats
-
Sodium / pharmacology
-
Sodium-Potassium-Exchanging ATPase / antagonists & inhibitors
-
Tumor Cells, Cultured
Substances
-
Carrier Proteins
-
Guanidines
-
Propionates
-
Ouabain
-
Sodium
-
Creatinine
-
Sodium-Potassium-Exchanging ATPase
-
guanidinopropionic acid