One Week Comparison Study of PTH and PTHrP Infusions

Inclusion Criteria: * Healthy African-American subjects of both sexes between the ages of 24-35 years, who are able to spend one week on the Clinical \& Translational Research Center (CTRC) at the University of Pittsburgh Medical Center (UPMC) Montefiore. Exclusion Criteria: * Subjects with cardiac, vascular, renal (serum creatinine \> 1.5), pulmonary, endocrine, musculoskeletal, hepatic, hematologic, malignant, or rheumatologic disease will be excluded. * Those found to have vitamin D deficiency, defined as a 25-OH vitamin D level \< 10 ng/mL will also be excluded. * Additionally, those with BMI \> 30, anemia (hematocrit \< 36% in women, \<40% in men), significant alcohol use, illicit drug use, hypertension (BP\>160/90), or baseline hypotension (systolic blood pressure \< 90mmHg) will be excluded. * Those taking chronic medications (except oral contraceptive pills (OCP's) or stable doses of thyroid replacement) or those who have received an investigational drug in the past 90 days will also be excluded. * Prior participants in PTH or PTHrP studies will not be eligible to participate. * Additionally pregnant women and lactating women will be excluded; all women will have a urine pregnancy test performed immediately before starting the study.