ATRIAL-NATRIURETIC-PEPTIDE REGULATION OF VERTEBRATE INTESTINAL ION-TRANSPORT

Atrial natriuretic peptide (ANP), in spite of its name, is synthesized and secreted in vertebrates by both the atria and the ventricles and also a number of extracardiac tissues. Likewise, the list of putative targets of ANP is large and includes, in addition to the kidney and va scular smooth muscle, the ion- and water-transporting intestine. Immun ohistochemical staining of the intestine of the euryhaline marine goby Gillichthys mirabilis demonstrates the presence of ANP-ergic neurons in the submucosa suggesting paracrine delivery to intestinal epithelia l and smooth muscle cells. ANP inhibits ion absorption across the goby intestine, supporting an osmoregulatory role for ANP.