Response of mouse hepatoma cell methylenetetrahydrofolate polyglutamates to folate deprivation

The behavior of methylenetetrahydrofolate polyglutamate conjugates in cultured mouse hepatoma cells which were starved of folate has been investigated. Folate deprivation caused methylenetetrahydrofolate levels to decrease an order of magnitude. This diminished pool consisted essentially completely of the octaglutamate form. Replenishment of the media with folate caused a slow recovery to normal levels of methylenetetrahydrofolate with undetectable quantities of shorter chain length polyglutamates observable during recovery. Leucovorin, on the other hand, caused a much more rapid recovery to normal levels and gave rise to the early appearance of short chain length polyglutamate intermediates.