Theory 26/Metabolic gradients/Mass spectrometry imaging
Gradients Are Steeper Than Assumed
The claim
Metabolite concentrations in tissue vary over tens of micrometres, so bulk assays report a value that exists nowhere in the sample.
01Mechanism
Supply and consumption create local gradients; bulk homogenisation averages across them.
02Prediction
Local concentrations should exceed the bulk average in supplied regions.
03Refutation
Homogeneous distributions at imaging resolution would remove the gradient claim.
04What makes it checkable
Mass spectrometry imaging now maps metabolites while preserving spatial position.
05Why it was not testable before
Bulk assays destroyed the spatial information by design.