ABSTRACT

I. Introduction ........................................................................... 110

II. Osteoporosis ........................................................................... 110

III. Parathyroid Hormone (PTH)................................................. 115 A. PTH, Stimulator of Bone Growth ................................. 115 B. The Osteogenic Signal ................................................... 118 C. A Plausible Osteogenic Mechanism.............................. 131 D. A Comparison of Anabolic Potencies ........................... 135

IV. Prostaglandins........................................................................ 137

V. Prospects ................................................................................ 140

Acknowledgments ............................................................................ 141

References ......................................................................................... 141

Osteoporosis silently stalks 1 of 3 women after she reaches menopause.1-3 This disease is said currently to afflict about 26 million people in Canada and the U.S. and 200 million worldwide. However, this number is challenged in Chapter 1 by Frost, who believes that true osteoporosis is much rarer and that most of these 26 million people really have a physiological osteopenia (i.e., they simply have less bone than their normal peers). Nevertheless, the number of elderly women (and men) with the osteopenia, bone pain, and the “spontaneous” fractures of true osteoporosis is growing as the populations of the two nations age. Indeed, both osteopenia and osteoporosis in both sexes will claim an increasingly large fraction of shrinking health budgets.1