The author substantially and expressly relied on the following publications for the information presented in this text: Deftos, LJ: Immunoassays for PTH and PTHrP In: The Parathyroids, Second Edition, JP Bilezikian, R Marcus, and A Levine (eds.), Chapter 9, pp.143-165, 2001. Deftos LJ and Gagel R: Calcitonin and Medullary Thyroid Carcinoma In: Cecil Textbook of Medicine, Twentieth First Edition, JB Wyngarden and JC Bennett, Chapter 265, pp.1406-1409, 2000. Deftos, LJ: Clinical Essentials of Calcium and Skeletal Metabolism, Professional Communication Inc, First Edition, pp. 1-208, (Figures 1,3-5 and Table 2) 1998 (Published on-line at Medscape.com). The following Chapters in Felig, P and Frohmer, LA. Endocrinology and Metabolism, 4th Edition, McGraw-Hill, 2001: Chapter 22, Mineral Metabolism, Bruder, Guise, and Mundy. Chapter 23, Metabolic Bone Disease, Singer. Chapter 27. Multiglandular Endocrine Disorders, Deftos, Sherman, and Gagel. Deftos, LJ: Hypercalcemia in malignant and inflammatory diseases. Endocrinology and Metabolism Clinics of North America, 31:1-18, (Figure 2) 2002.

ACKNOWLEDGEMENTS: This work was supported by the National Institutes of Health and the Department of Veterans Affairs. Dr. Deftos has no relevant conflicts of interest, commercial or otherwise.