DNA Synthesis in Nuclei and Mitochondria Purified from Serum-Free or Supplemented Glial Cell Cultures

Abstract

Nuclear and mitochondrial DNA synthesis in serum-free or supplemented rat glial cell cultures at different days after plating was studied. Furthermore in mitochondria purified from bells grown in basal nutrient medium some enzymatic activities related to energy transduction (citrate synthase, malate dehydrogenase, total NADH-cytochrome c reductase, cytochrome oxidase and glutamate dehydrogenase) were measured. [Methyl- ³H] thymidine was added at different days after plating to the serum-supplemented and to the serum-free culture media. During the period tested the specific activity of total, nuclear and mitochondrial DNA decreased from 8 DIV to 21 DIV and increased at 30 DIV in the serum- supplemented glial cell cultures; on the contrary, it decreased from 15 DIV up to 32 DIV in the serum-free cultures. The specific activity of nuclear DNA was always higher than that of mitochondrial DNA. In the serum-supplemented cultures the specific activity of the above mentioned mitochondrial enzymes increased from 8 DIV up to 21 DIV, and decreased at 30 DIV.