ATRIAL NATRIURETIC PEPTIDES IN THE HEART AND HEMOLYMPH OF THE OYSTER,CRASSOSTREA-VIRGINICA - A COMPARISON WITH VERTEBRATES

1. The content of atrial natriuretic peptides (ANPs) in the auricles o f oysters, Crassostrea virginica, was significantly (P < 0.01) greater than in their ventricles. 2. High-performance gel permeation chromato graphy (HP-GPC) followed by ANF radioimmunoassay revealed two peaks in both oyster and vertebrate (rat) hearts-a major peak where the 12.6-1 4 kDa ANF prohormone elutes and a smaller peak where the pure human fo rm of ANF elutes. 3. HP-GPC evaluation followed by proANF 31-67 radioi mmunoassay revealed only an ANF-like prohormone while HP-GPC followed by proANF 1-30 radioimmunoassay revealed the ANF prohormone and a proA NF 1-30-like peptide in oyster and rat hearts. 4. ANPs concentrations in hemolymph were 940 +/- 129, 225 +/- 25, and 100 +/- 10 pg/ml by the proANF 1-30, proANF 31-67, and ANF radioimmunoassays, respectively. 5 . Atrial natriuretic-like peptides are present in the oyster heart in molecular species similar to vertebrate species and these peptides are also present in hemolymph.