l-glutamine concention in raw 264.7 - (Oct/27/2011 )

I ordered DMEM with 4 mM of L-glutamine. However, my pen-strep solution also contains 2 mM of L-glutamine. Is 6 mM a good concentration for raw 264.7 cells? Otherwise, I also have some media without L-glutamine. So would it be preferable to use 2 mM of l-glutamine or 6 mM?
Thanks!

It deppends, sometimes higher concentration of glutamine could maintain your cells on the Lag fase (and depends on how much are you seeding at) , So I would recomend you to prepare the media without glutamine and adjust the concentration as you desire (try a test with 0.5mM, 1mM, 1.5mM and 2.0mM) and choose the better for your experiment.

For example my (a-549) cell were using a 0.5mM glutamine concentration with a doubling time of 23hr , and later I made some tests with 2mM glutamine, The result was a better viability and morphology, the doubling time decrease to 18hrs per day.

I hope this would be helpful for you.

I think it might also be worthwhile sitting down and having a think about what happens to the concentration of various solutes when you mix solutions. You won't be getting 6mM by adding a 2mM solution to a 4mM solution- as the volume will change.