[NTG-context] Metapost graph : format of numbers

Hello I would like to know whether it is possible or not to force MP graph to display big numbers in labels (of y axis) in a normal format (for example 50000) and not in scientifical format (for example 5x10^4). I could not manage to do it. It would be even better if the solution worked with log scale as well. If it is not possible with MP graph, I ask the same question for pgfplots. If it is not possible either, would anybody have another idea ? Thanks and goodbye, Stéphane.