Since the first demonstration of the activity of human and monkey pituitary growth hormone (GH) extracts in humans (1,2), research regarding the effect of GH on bone have focused primarily on the hormone's promotion of linear growth. In the last decade, however, the importance of the role of GH in bone metabolism has become increasingly apparent. Recent research has demonstrated that GH administration stimulates osteoblast proliferation and promotes bone formation in vitro and in vivo, and that GH deficient states are associated with osteoporosis. In addition, normal aging has been shown to be associated with both declining GH secretion and declining bone density, suggesting a possible link between GH and senile osteoporosis. A number of technical advances have aided this work. In vitro studies have been advanced by new cell-culture techniques and recombinant DNA technology. Studies of bone metabolism in humans have assessed bone turnover with a widening array of serum and urine markers. These include osteo-blast markers, byproducts of bone formation, and urine markers of bone resorption. Furthermore, refinements in the measurement of bone mineral content and bone density have permitted long term studies of the effect of GH administration on bone mass. This chapter will address the relationship between GH and osteoporosis by reviewing in vitro studies of GH and bone cells, studies of patients with GH deficiency, and studies of GH administration using different model systems.

From: Human Growth Hormone: Research and Clinical Practice Edited by: R. G. Smith and M. O. Thorner © Humana Press Inc., Totowa, NJ

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