Peptide messengers, and therefore their precursors and the enzymatic processing
machinery, largely antedate their actual physiological integration in modern species. The
current names derived from present functions or organs are misleading with regard to their
evolutionary origin. For example the so-called'neurohypophysial'peptide systems have
existed long before the emergence of vertebrate neurohypophysis. An immunoreactive
oxytocin/vasopressin-like peptide has been detected in the neural network of the freshwater …