Conversation so far:
the walls of the atria produce which hormone
Specialized cells in the wall of the atria produce and secrete the peptide hormone atrial natriuretic peptide (ANP).
what does the hormone atrial natriuretic peptide do
ANP signals the kidneys to reduce sodium reabsorption, thereby decreasing the amount of water reabsorbed from the urine filtrate and reducing blood volume.

Question: what else does it do
Self-contained rewrite: what else does ANP do