ATRIAL-NATRIURETIC-PEPTIDE IMMUNOREACTIVITY IN THE EGGS OF THE SILKWORM BOMBYX-MORI

Synthesis and secretion of atrial natriuretic peptides (ANPs) are not confined to the atrium, but are also present in other tissues. Recentl y, we have found synthesis of ANP in the eggs of several vertebrate an imals. The present study was undertaken to determine whether immunorea ctive ANP (irANP) is present in the egg of an invertebrate, the silkwo rm (Bombyx mori L.). The serial dilution curve of egg extracts of silk worm was parallel to the standard curve of atriopeptin III. Analysis o f ANP immunoreactivity by gel filtration chromatography and reverse-ph ase HPLC showed that the major immunoreactivity corresponded to rat pr oANP. The semipurified irANP of egg extracts produced a dose-dependent relaxation on rat aortic strips, which was blocked by preincubation w ith anti-ANP antiserum. Therefore, we suggest that ANP is synthesized in the silkworm egg. (C) 1994 Academic Press, Inc.