Glucocorticoids are potent anti-inflammatory and immunosuppressive agents. However, prolonged use of these potent agents results in severe bone loss and osteoporotic fractures. Parathyroid hormone (1-34), when given as a daily injection has been found to dramatically increase bone mass in osteoporotic animals and postmenopausal women. The purpose of this study is to determine whether 2 years of daily PTH (1-34) injections will increase bone mass and reduce the development of new fractures. In addition, we will follow the study subjects for 2 more years to determine which type of anti-resorptive agent is required to maintain the newly formed bone. We are enrolling postmenopausal women that are on chronic corticosteroid therapy (prednisone etc.) and have bone loss (osteopenia by DXA) to be a part of this four-year-long study. The patients will receive two-year therapy with either PTH (1-34) or placebo, and for the second part of the study subjects receive either estrogen and placebo or alendronate and placebo. We will measure bone gain by standard bone densitometry, special x-rays of the spine and hip, and serum and urine bone markers.