The atrial gland of the marine mollusk Aplysia californica is an exocrine organ that expresses at least three genes belonging to the egg-laying hormone (ELH) family. In order to study the post-translational processing of the ELH-related gene products in the atrial gland and how it compares to the bag cells, peptides were isolated from the atrial gland and chemically characterized. The A- and B-...