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Metabolic Action of Parathyroid 

 Hormone on Rat Calvaria 



C. M. DOWSE, M. W. NEI MAN, K. LANE, and W. F. NEUMAN, 



Department of Radiation Biology, School of Medicine and Dentistry, 

 University of Rochester, Rochester, New York 



DESPITE a long history of polemical argument, it is now generally 

 agreed that parathyroid hormone has a direct action on bone, caus- 

 ing an increase in the population of resorbing cells, the osteoclasts, 

 a mobilization of bone mineral, and perhaps a general increase in 

 the availability of the bone mineral, at least for exchange with 

 parenterally administered isotopes (Creep and Talmage, 1961; Neu- 

 man and Neuman, 1958). More recently, attention has focused on 

 possible hormonally induced changes in cellular metabolism in bone. 

 Presumably an understanding of these metabolic changes might 

 clarify the biochemical mechanisms by which the hormone exerts 

 its osteolytic eflFects. 



Bone, however, is so obviously unsuited for conventional bio- 

 chemical studies of metabolism that progress has been rather limited 

 and published reports have been few (Laskin and Engel, 1956; Borle 

 et al, 1960a, 1960Z?; Lekan et al, 1960; Neuman and Dowse, 1961; 

 Cohn and Forscher, 1961, 1962fl, 1962Z?; Vaes and Nichols, 1961, 

 1962; Schartum and Nichols, 1961, 1962). In most cases crushed or 

 sliced metaphyses have been employed despite the obviously serious 

 contamination by marrow cells. The investigations reported below 

 were conducted on the calvarium of the newborn rat. 



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