Several important peptide hormones are secreted from the pituitary gland. The anterior pituitary secretes three hormones: prolactin , which acts on the mammary gland ; adrenocorticotropic hormone (ACTH), which acts on the adrenal cortex to regulate the secretion of glucocorticoids ; and growth hormone , which acts on bone , muscle , and the liver . The posterior pituitary gland secretes antidiuretic hormone , also called vasopressin, and oxytocin . Peptide hormones are produced by many different organs and tissues, however, including the heart ( atrial-natriuretic peptide (ANP) or atrial natriuretic factor (ANF)) and pancreas ( glucagon , insulin and somatostatin ), the gastrointestinal tract ( cholecystokinin , gastrin ), and adipose tissue stores ( leptin ).  
Lysyl oxidase has been newly implicated in tumor angiogenesis , or blood vessel formation, both in vivo and in vitro . Subcutaneous tumor-derived LOX was shown to increase vascular endothelial growth factor (VEGF) expression and secretion, which then promotes angiogenesis by phosphorylation of protein kinase B , or Akt, through platelet-derived growth factor receptor β ( PDGFRB ). High levels of LOX were associated with high blood vessel density in patient samples. Clinically relevant LOX inhibitors may help slow cancer progression by downregulating crucial growth factors that promote solid tumor progression.