Change in ATP and ADP content of fasting and feeding planarians (Polycelis nigra).

The ATP and ADP content of planarians subjected to starvation for two weeks followed by feeding for the same period was investigated. The ATP and ADP content during fasting increased and then, after feeding, returned to normal. The ATP/ADP ratio varied in the same way, which is consistent with the view that the adenylic nucleotide pool is implicated in the regulation of the energy metabolism of the organism.