ATP-dependent uptake of Ca2+ by a microsomal fraction from rat incisor odontoblasts.
Intracellular vesicles containing alkaline phosphatase and Ca2+-ATPase activity were isolated in the microsomal fraction from free-dissected odontoblasts of rat incisors. The microsomal fraction was incubated with 45Ca2+ to study Ca2+ uptake. ATP stimulated Ca2+ uptake, whereas little uptake occurred without ATP. The maximal effect was obtained with 3mM ATP. The ATP-dependent uptake was linear for 2 h. Increasing the pH up to pH 8.2 resulted in an increased uptake. Mg2+ was stimulatory with an optimal effect at a 6mM concentration. Increasing concentrations of Ca2+ up to 100 micrometer enhanced the uptake. A correlation between Ca2+ uptake and Ca2+-ATPase in intracellular vesicles as well as a possible function in the calcification process are discussed.
D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007180:Incisor / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008861:Microsomes / Q000378:metabolism*; D009804:Odontoblasts / Q000378:metabolism*; D051381:Rats
D000252:Calcium-Transporting ATPases; D002118:Calcium