Growth Hormone's Effect on Endothelial Progenitor Cells

Inclusion Criteria: * Adults age 18 thru 65 * Serum IGF-1 in the lower half of the age and gender-specific normal range at the time of screening visit Exclusion Criteria: * Systemic hypertension, as defined as current BP \>140/90 on screening visit, or taking anti-hypertensive therapy. * Diabetes mellitus, as defined by known diagnosis or Fasting Blood Glucose \>126 at the time of screening visit. * Women who are pregnant or nursing, as confirmed by history or seum beta-hCG at the time of screening visit. * Women who are taking exogenous oral estrogens of any kind. * Personal history of active cancer or recurrence within the past 10 years, with the exception of non-melanoma skin cancer. * Personal history of an untreated benign intracranial neoplasm. * Initiation of statin therapy during the course of the study. * A serum IGF-1 level below the age and gender-specific normal range at the time of screening visit. * Renal insufficiency, as defined by a GFR \<60 mls/min/1.73 m2 upon Renal Function panel at the time of screening visit. * Hepatic insufficiency, as defined by an AST and/or ALT \>twice the upper limit of normal at the time of screening visit.