Suspected Deficient Activation of Vitamin D in Patients With Secondary Hyperparathyroidism

Inclusion Criteria: * Caucasian female * Age 40-59 years * Serum creatinine \< 1.3 and estimated glomerular filtration rate (GRF) \> 60 * Serum calcium in the normal range (for U Md lab 8.6-10 mg/dl) * Parathyroid hormone in the normal range (for U Md lab 12-54 pg/ml) * Normal 25-hydroxyvitamin D level (30 ng/ml or higher) * For women of childbearing age, non-pregnant (based on negative urine pregnancy test on the morning of the teriparatide infusion) Exclusion Criteria: * Non-caucasian * Age under 40 and over 59 years * Male * Serum creatinine over 1.3 or estimated glomerular filtration rate (GFR) \< 60 * Abnormal serum calcium (for U Md lab, below 8.6 or above 10 mg/dl) * Abnormal parathyroid hormone (for U Md lab, above 65 or below 12 pg/ml) * For women of childbearing age, non-pregnant (based on urine pregnancy test on the morning of the teriparatide infusion) * History of bone radiation * History of Paget disease of bone * History of bone malignancy or metastases * History of allergy or sensitivity to Forteo