What is the fine-grained topic of the following text: There are at least three major natriuretic peptides that have been discovered: atrial natriuretic peptide (ANP)- secreted largely by the atria; brain natriuretic peptide (BNP) - produced by the ventricles and C-type natriuretic peptide (CNP)- located in peripheral blood vessels. Only return the topic.
Types of Natriuretic Peptides