G. Nichols, Jr.: Bony Targets of Non-"skeletal" Hormones 215 



fusion might help to estabHsh the diagnosis in those patients in whom the diagnosis 

 remains in some doubt. The importance of relating clearance or re-absorption to the 

 level of plasma ultrafilterable calcium is stressed as the percentage re-absorption falls 

 in all three groups of patients as the plasma ultrafilterable calcium rises. If this is not 

 taken into consideration an apparently lower tubular re-absorption of calcium will 

 be seen in patients with primary hyperparathyroidism as they have a higher ultra- 

 filterable calcium than normal subjects. 



References 



Bernstein, D., C. R. Kleeman, and M. H. Maxwell: The effect of calcium infusions, para- 

 thyroid hormone and vitamin D on renal clearance of calcium. Proc. Soc. exp. Biol. 112, 

 353 (1963). 



GoRDAN, G. S., H. F. LoKEN, A. Blum, and J. S. Teal: Renal handling of calcium in para- 

 thyroid disorders. Metabolism 11, 94 (1962). 



Kleeman, C. R., R. E. Rockney, and M. H. Maxwell: The effect of parathyroid extract 

 (PTE) on the renal clearance of diffusible calcium. J. clin. Invest. (Abstract) 37, 907 

 (1958). 



Loken, H. F., and G. S. Gordan: Renal mechanisms in the production of hypercalcaemia in 

 hyperparathyroidism and breast cancer. J. clin. Invest. (Abstract) 38, 1021 (1959). 



MacFadyen, I. J., B. E. C. Nordin, D. A. Smith, D.J. Wayne, and S. L. Rae: Effect of 

 variation in dietary calcium on plasma concentration and urinary excretion of calcium. 

 Brit. med. J. 1, 161 (1965). 



McPherson, G. D.: Regulation of plasma calcium in man. Thesis. University of British Co- 

 lumbia 1959. 



ToRiBARA, T. Y., A. R. Terei'KA, and P. A. Dewey: The ultrafilterable calcium of human 

 serum. I. Ultrafiltration methods and normal values. J. clin. Invest. 40, 738 (1957). 



Bony Targets of Non-"skeletar' Hormones 



G. Nichols, jr. 

 Harvard Medical School, Department of Medicine, Boston, Mass., U.S.A. 



Even the most superficial review of the older literature in endocrinology quickly 

 reveals that there was a time when skeletal changes were considered to be among the 

 important features expected in any endocrine disorder. It seemed obvious, for 

 example, that changes in skeletal growth should be a prominent if not central feature 

 of disturbances of pituitary function and growth hormone secretion. Thus, as the 

 etfects of other endocrine glands — thyroid, adrenal, gonads — began to be explored 

 it was not surprising that the list of organ systems examined almost always included 

 the skeleton. Thanks to this broad view a considerable number of empiric observa- 

 tions about hormonal effects on bone gradually accumulated (Silberberg and Silber- 

 BERG, 1956; AsLiNG and Evans, 1956). In some instances this search for skeletal 

 eft'ects was richly rewarded, as in the case of the parathyroids. In others, the effect 

 could only be clearly shown in certain species as for example the marked influence of 

 female sex hormones on avian bone (Kyes, 1934). In still another group — the 

 thyroid and adrenals are good examples — while effects on the skeleton were seen 

 these were far less dramatic than the effects observed in other organs and systems. 



