BIOSYNTHESIS OF NEUROPEPTIDE-Y IN PORCINE TISSUES AND GENERATION OF N-TERMINAL FRAGMENTS IN NEUROBLASTOMA CELL-LINES

The biosynthesis of neuropeptide Y (NPY) was investigated to determine the efficiency of synthesis and processing of the precursor. In brain tissues examined, the major product was amidated NPY(1-36). Although this was also the major product in adrenal and heart atrium, a minor p ortion of the immunoreactivity was identified as unprocessed precursor . NPY degradation was investigated using SK-N-MC and SMS-MSN cells in conjunction with iodinated NPY tracers, labeled in either the tyrosine -1 or the tyrosine-36 position. Similar patterns of degradation were o bserved with both cell lines, and it would appear that the initial pro teolytic attack on NPY(1-36) generates predominately N-terminal fragme nts.