This is a voluntary study. Adult patients with a diagnosis of acromegaly or a clinically nonfunctioning pituitary tumor receiving treatment at the Emory University Pituitary center will be given the opportunity to enroll in the study. Those that agree to participate will need to give written informed consent. Approximately 3 tablespoons (44ml) of blood will be drawn at enrollment for testing of vitamin D status and parathyroid hormone. If patients are already undergoing a blood draw for standard laboratory tests, then the volume of 44ml of blood will be obtained at the same time in order to avoid an additional needle stick. In addition, a 24-hour urine collection will be obtained to assess the amount of calcium present in the urine. Please note that medical or surgical therapy for your pituitary condition is determined by your endocrinologist and/or neurosurgeon and not part of the research study.