Never use this cell line before. Here is the link from Sigma regarding the L-Glutamine.

http://www.sigmaaldrich.com/life-science/cell-culture/learning-center/media-expert/glutamine.html

According to SIGMA comment, '' L-glutamine is an unstable essential amino acid required in cell culture media formulations. Most commercially available media are formulated with free L-glutamine which is either included in the basal formula or added to liquid formulations at time of use. L-glutamine is unstable at physiological pH in liquid media. It breaks down to ammonium and pyroglutamate at rates that make it a problem in many biomanufacturing applications. Today several proprietary media used in biomanufacturing are supplemented with L-glutamine in dipeptide forms, such as alanyl-l-glutamine and glycyl-l-glutamine. Because of its chemical instability and importance for cell growth and function, it is critical that the delivery of L-glutamine be optimized to each unique cell culture process. Hence the effective use of L-glutamine and L-glutamine equivalents in cell culture requires an understanding of its chemistry and multiple delivery forms.''

Which would be the effects of theL-glutamine break down products on the cells?

Ammonia not only inhibits the growth of cell, but also reduces the cell density and antibody production. C-terminus of pyroglutamate may lead to influence fiber morphology of Abeta peptides and the N-terminus interacts with cell membrane.

i use this cells with glutamate from invitrogen, which is stable compared to l-glutamine

L-glutamine is one of the major sources of energy in media. Usually after a passage the need of cells to glutamine rises up, so you should care about level of L-glutamine in your media. This need will be more if you are using a low glucose media.

what happens if you add more L-glutamine than what is already contained in commerical media? is this fatal to cells?

It might help you to use media with Glutamax to reduce the potential downside of glutamine breakdown. An alternate would be to change media every two days...

thanks God. Im struggling to grow Pancreatic cells and I BELIEVE THIS WILL HELP.

Yeah had same issue with pancreatic cell line. Adding extra L-glutamine seems to halt their growth and proliferation. 

TCM 199 supplemented with 10% fetal calf serum (FCS) is commonly used In vitro maturation

In cell culture systems, L-Glutamine serves as a crucial component of culture media. It is used extensively in wide range of media including classical media, serum-free media, insect cell culture media and media for hybridoma culturing. It plays many important roles in cell culture. Some of them are mentioned below:

• Energy source L-Glutamine serves as an alternative source of energy for rapidly dividing cells and cells that use glucose inefficiently. L-Glutamine is readily available amino acid for energy production when carbohydrate energy source is not available or deprived in culture medium.

• Reservoir of nitrogen for synthesis of proteins, nucleic acid and other nitrogenous compounds: L-Glutamine is converted to ammonium and pyroglutamate inside the cells. Cells utilize these ammonium ions for formation of amine of glutamate or amide of glutamine. These two amino acid derivatives serve as primary reservoirs of nitrogen for synthesis of proteins, vitamins, nucleic acids and other nitrogenous compounds such as NAD, NADH.

• Precursor of glutamate: L-Glutamic acid generated from catabolism of LGlutamine serves as a precursor for synthesis of alpha amino acids.

• Growth-limiting amino acid: L-Glutamine acts as a growth-limiting amino acid in culture media and hence is required at a 5- to 20-fold greater concentration than other amino acids.

Kalthoum Abid : This is wrong. glutamine is not an essential amino acid for mammals as we express glutamine synthetase.

only for GS knock out cell lines this amino acid is essential

Thank you Dr Konstantin, you are absolutely right. I am sorry I omitted to write conditionally, I wanted to say that Glutamine is an amino acid conditionally essential, because under special pathophysiological conditions it could be considered conditionally essential.

Glutamine is an amino acid used in a serum free supplement in cell culture media. It supports the growth of cultured cells, as it intervenes in the synthesis of proteins and nucleic acids.

For letting the culture at 37 degrees Celsius overnight, I think that Glutamine is sufficiently stable at this temperature, since it protects the cell by involving the expression of heat shock proteins.

Energy production, cell maturation, synthesis of nitrogenous compounds owing to N, help to electron transfer due to N of NADH/NAD and toxicity reduction are mentioned for L-Glutamine role in the media.

So, it's inactivation may harm any of the above.

Also, increasing it too much in the media may cause the production of ammonia, which is dangerous for the cell.