Pancreastatin-like immunoreactivity in the pancreas of newborn rats

Pancreastatin (PST), a novel COOH-terminally alpha-amidated peptide is a part of Chromogranin A molecule. Precursor processing implies also the final amidation step dependent on peptidylglycine alpha-amidating monooxygenase (PAM). High activity of PAM as well as Thyroliberin (TRH, another alpha-amidated peptide) concentration and biosynthesis were reported to be very high in neonatal rat pancreas. We followed the concentration of PST-like immunoreactivity in rat pancreas during ontogenesis. High perinatal PST concentration, resembling that of previously reported for PAM activity and TRH concentration was found. These findings suggest that perinatal PAM activation may affect a broader spectrum of pancreatic peptides.