"PTHrP(1-36) IV Dose Escalation Study"

This is a single-blinded, one-treatment, combination dose escalation and pharmacokinetic study done in healthy volunteers. The investigators want to determine whether Parathyroid Hormone related Protein (1-36) \[PTHrP(1-36)\] shares anabolic properties with the only currently approved anabolic agent, parathyroid hormone(1-34) \[PTH(1-34)\], which stimulates both osteoblastic bone resorption and formation. In a previous study done by the investigators, postmenopausal osteoporotic women on estrogen received 6.56 mcg/kg PTHrP(1-36) subcutaneously for three months daily. They experiences a 4.7% increase in bone mineral density (BMD) of the lumbar spine when compared with those taking placebo. They also displayed an increase in serum osteocalcin, a marker of bone formation, with no change in several markers of bone resorption. It is believed that the rapid absorption and clearance of PTHrP(1-36) likely plays a central role in its anabolic effect In order to further assess absorption, we are combining both pharmacokinetic and dose escalation methods for studying intravenous PTHrP given via a one-time bolus injection. The purpose is to define the maximum safe dose and measure the pharmacokinetic parameters of a single intravenous dose of Parathyroid Hormone-related Protein (1-36)\[PTHrP(1-36)\]. The results will be useful in determining future treatment options for osteoporosis.