The purpose of this study is to evaluate hormone values and other markers of disease activity in a cohort of patients with acromegaly at the time of diagnosis and then prospectively after surgical or other treatment. This study is designed to determine blood levels of growth hormone and related hormones and cardiovascular risk markers as well as signs and symptoms of the disease at diagnosis and how these parameters change over time after surgical or other therapy. The investigators will also obtain hormonal data in a group of 50 healthy subjects who will each be studied just once with an oral glucose tolerance test (OGTT). These data will provide a comparison group to the acromegaly subjects.

Surgical removal of the pituitary tumor is the usual first form of treatment offered, but this is curative in only approximately 70% of patients. If not adequately treated, the disease can have significant morbidity largely due to the development of hypertension, diabetes and malignancy as well as possible loss of vision or other neurologic complications of a large pituitary mass. Inadequately treated acromegaly is also associated with a mortality rate 2-3 fold over the general population. All the mechanisms responsible for the increased morbidity and mortality in acromegaly as well as what biochemical criteria should be used during treatment in order to normalize the increased morbidity and mortality are not known. This study aims to follow patients with acromegaly prospectively from active disease through treatment in order to identify these factors.

Acromegaly Subjects

Inclusion Criteria:

• Adult males and females.
• Ages 18 and over.
• Presenting to the PI or one of the sub-investigators for evaluation of acromegaly.
• Must have a biochemical diagnosis of acromegaly consisting of an elevated serum insulin-like growth factor 1 (IGF-1) level. Supportive although not required for entry are an elevated growth hormone (GH) level and a failure of GH to suppress normally after oral glucose administration.
• Willingness to participate in this study's procedures.

Exclusion Criteria:

• Subjects who are unwilling to comply with the procedures outlined in the study.
• Subjects who do not have the ability to fully comprehend the nature of the study, to follow instructions, and/or cooperate with study procedures
• Are unwilling to provide informed consent to participate in the study.

Healthy Subjects

Inclusion Criteria:

• Adult males and females.
• Ages 18 and over.
• Responding to ads for participation or by word of mount.
• No medical problems, no medications, stable weight for 3 months prior to study.
• Willingness to participate in this study's procedures.

Exclusion Criteria:

• Subjects who are unwilling to comply with the procedures outlined in the study.
• Subjects who do not have the ability to fully comprehend the nature of the study, to follow instructions, and/or cooperate with study procedures
• Are unwilling to provide informed consent to participate in the study.
• Failure to meet the inclusion criteria.

Subjects newly diagnosed with acromegaly or who have previously undergone surgery for acromegaly are invited to participate.