PPY and schizophrenia: Expression of various hormones was found to differ significantly between patients with schizophrenia and control subjects: insulin, prolactin, pancreatic polypeptide, progesterone and chromogranin A (a protein of the granin family composed of 439 amino acids that is located in the large dense-core vesicles of the neuroendocrine cells) were increased, while growth hormone was decreased in patients with schizophrenia compared to control subjects [67].