Integrating Endocrine and Paracrine Influences on Bone: Lessons from Parathyroid Hormone and Parathyroid Hormone-related Protein

Abstract

Bone remodeling and calcium homeostasis are regulated by the concerted actions of circulating hormones and paracrine cytokines and growth factors. This chapter uses the example of how parathyroid hormone (PTH) and the paracrine PTH-related protein (PTHrP), which act upon a common G protein-coupled receptor (PTH1R), share roles in skeletal physiology. Studies in human patients, mouse genetics and cell culture have revealed distinct roles for these proteins, despite their common receptor. In postnatal life, PTH predominantly controls calcium homeostasis through actions on bone, kidney and intestine, whereas PTHrP, produced by osteoblast lineage cells, acts locally to promote bone formation and..