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Some Remarks and Questions on Metabolic Patterns in the Family 



of Bone Cells 



W. A. DE VoOGD VAN DER StRAATEN 



Laboratorium voor Celbiologie en Histologie, Rijksuniversiteit Leiden, Leiden, 



Nederland 



In order to speak sensibly about metabolic patterns in the family of bone cells at 

 least three general points have to be clarified. The first point concerns the way in 

 which the word family is used; the second point concerns the concept of metabolic 

 pattern in general; and the last point concerns the Interconnection between some pure 

 scientific and methodological questions in our special field. 



1. By definition the members of a family are relatives, and they remain so even if 

 they are miles apart. Now the different types of cells found in bone tissue, the bone 

 cells, are relatives but they are not miles apart; on the contrary the members of the 

 family of bone cells live closely together and form a functional and structural unit. 

 In what I am going to say about bone cells, however, I will not look upon them 

 as relatives but as different types of labourers in a "family factory". 



2. It is common knowledge that the morphologically comparable cellular elements 

 of a tissue e. g. osteocytes, are not by necessity all in the same functional state at the 

 same time. "Without discussing the background of this phenomenon, I think that none 

 of us would attribute these variations to differences in metabolic pattern. What then 

 is covered by this term and what is the special meaning of the word pattern? Or to 

 restate this problem in a positive way, why do we in all probability suppose different 

 metabolic patterns to be existent in osteoblasts and osteoclasts even if we have no 

 pertinent biochemical data at hand? To my mind a list of biochemical differences 

 would not necessarily imply different metabolic patterns. Such a list would deserve 

 our full attention and would be a challenge, stimulating our Ingenuity In making 

 connections between these biochemical differences and the essential differences in 

 function, the cells are known to have in the tissue. It Is only from the moment that 

 we have succeeded in making reasonable connections that we are allowed to speak of 

 different metabolic patterns. To press this point a little further, it is clearly a matter 

 of convention how to define the term metabolic pattern. In fact I prefer an opera- 



