12-plex DiLeu enables robust quantification of the feeding neuropeptidome

Understanding the feeding-induced neuropeptidome cascade requires analytical strategies capable of quantifying low-abundance, highly modified peptides across multiple tissues and time points. Herein, we apply 12-plex N,N-dimethyl leucine (DiLeu) isobaric labeling to perform the first multiplexed, tissue-wide, temporal quantitation of the Cancer borealis feeding neuropeptidome. This approach enabled sensitive measurement of neuropeptides across five tissues over six timepoints, revealing distinct regulatory patterns. The pericardial organ (PO) showed rapid early upregulation followed by suppression aligned with foregut emptying, whereas the thoracic ganglion (TG) displayed inverse and strongly condition-dependent responses, indicating previously unrecognized neuromodulatory roles. Single-residue variants and post-translational modifications, including pyro-Glu formation and amidation, produced markedly different temporal profiles, underscoring the functional specificity of closely related isoforms. We further identify differential regulation of proctolin and its amidated form, suggesting modified variants may contribute uniquely to feeding physiology. Collectively, these results establish multiplexed DiLeu labeling as a powerful platform for quantitative neuropeptidomics and reveal new dimensions of peptide-mediated feeding regulation.