PRL and panhypopituitarism: Hypopituitarism can present as a deficiency of individual anterior pituitary hormones (e.g., adrenocorticotropic hormone, thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, prolactin, growth hormone) or posterior pituitary hormones (e.g., oxytocin, vasopressin) or as the deficiency of all these pituitary hormones, also known as panhypopituitarism.