BONE RESORPTION IN TISSUE CULTURE 



Hydroxyproline-H^ found in medio hydroiyzotes of 



parathyroid extrad-treoted cultures vs. controls 



(Cumulative DPM/ml wtiole media hydrolyzate) 



3500 



]^ 3000 



< 



N 



^ 2500 



O 



a: 



Q 



^ 2000 



(HI 



_J 



UJ 



> 



^ 





Q 

 UJ 



500 



LH 1000 



o 



X 



500 



6 8 

 DAYS 



10 



14 



Fig. 28C. Same data as shown in Fig. 28B, bnt graphed as cumulative 

 counts. Note that at the end of 2 weeks the cumulative count of hvdroxvprohne- 

 H'^ per ml of media hydrolyzate of parath\ roid extract-treated cultures totals 

 more than 3 times the value derived from the control cultures. (Data repro- 

 duced from Stern ct al, 1963fl, 1963/;.) 



X 



^ 



claimed (McLean, 1956), his similar findings of intense bone resorp- 

 tion with crystalline vitamin A and calciferol ( Barnicot, 1948 ) have 

 not received much attention in this countr>'. Although his experi- 

 ments stronglv suggested a direct effect of these agents on iDone, 

 clear-cut proof of such a potential can be obtained only in tissue 

 culture. Such evidence has been obtained for parathyroid tissue and 

 extract, as discussed earlier in this paper. Similar evidence of a 

 direct effect of n itamin A on bone in tissue culture has been ac- 

 cumulated during the past decade bv Dr. Honor B. Fell and her 

 co-w^orkers. Fell and Mellanbv ( 1952 ) found that addition of xitamin 

 A acetate or alcohol to the medium resulted in a profound effect on 



