Synthesis of multiple peptides from a larger precursor in the neuroendocrine caudo-dorsal cells of Lymnaea stagnalis

Abstract

The biosynthesis, transport and release of multiple peptides by the egg-laying controlling neuroendocrine caudo-dorsal cells (CDCs) of Lymnaea stagnalis were studied. High-performance gel permeation chromatography was used to resolve newly synthesized peptides after pulse-chase experiments with radioactive amino acids. The ultimate precursor is a ∼35 kd (K) peptide which is produced in the CDC somata. It gives rise to intermediate products (∼20 K, ∼10 K and ∼7 K) and a number of end products which include a ∼4.5 K peptide (the ovulation hormone) and other peptides (∼6 K, ∼3.5 K and ∼2 K). The end products are transported in neurosecretory granules to the CDC axon terminals in the cerebral commissure where they are released into the medium during electrical discharges of the CDC system.