J. A. Fernandez de Valderrama, L. M. Munuera: The Effect of Cortisone 245 



0.7 — 1.5"/o. The suppression of mitosis in the preosteoblasts results in a delayed 

 chondrocytolysis and therefore in a delay of the longitudinal growth (Table 2). 



Finally we treated 5—6 month old male Swiss mice, weighing approximately 

 25 g, daily by intraperitoneal injections of 2 mg estrogen or testosterone. The mice 

 were killed 7, 13, 20 and 27 days after the beginning of the experiment. 



In testosterone treated mice the proliferation-index of the preosteoblasts remains 

 unchanged at the normal value of 7^lo. In contrast, estrogen increases the pro- 

 liferation-index of the preosteoblasts from 7^lo to 16Vo after the first week of treat- 

 ment, which then stabilizes at 33Vo (Table 2). The increase of preosteoblasts causes an 

 exceptional increase of endochondral, endosteal and periosteal new bone formation. 

 A weight comparison of bone tissue to the total metaphysis yields a percentage of 

 28.6 for the control mice, 24.6 for the testosterone treated mice, and 39.6 for the 

 estrogen treated mice. 



In conclusion: The combined method of light microscopic and autoradiographic 

 investigation offers a clearer and finer understanding as to the exact influence of 

 hormones on the endochondral ossification. The transposition of these experimental 

 results from animal to man is not within the scope of this work. 



References 



HoLZER, F.: Autoradiographische Untersuchungen iiber die Zellkinetik der enchondralen 



Ossifikation der Maus nach Oestrogen- und Testosteronverabreichung. Z. ges. exp. Med. 



139, 213 (1965). 

 RoHR, H. p.: Reifung der Knorpelzellen der Epiphysenfuge bei der experimentellen Ratten- 



rachitis. Z. ges. exp. Med. 137, 532 (1963). 

 — Autoradiographische Untersuchungen iiber den Wirkungsmechanismus des Cortisons (17- 



oxy-dehydrocorticosteron) auf das enchondrale Knochenlangenwachstum der Ratte. Z. ges. 



exp. Med. 138, 150 (1964). 

 Uehlinger, E., H. p. Rohr und F. FioLZER: Uber den Wirkungsmechanismus von Thyroxin 



und Thiouracll auf das enchondrale Knochenlangenwachstum der Ratte. Z. ges. exp. Med. 



(In press). 



The Effect of Cortisone and Anabolic Agents on Bone 



J. A. Fernandez de Valderrama, L. M. Munuera 



Nuffiekl Orthopaedic Centre, Oxford, England 

 Now: Madrid, Espafia 



An excess of cortisone causes an osteoporosis which resembles that of Cushing's 

 syndrome (Sissons, 1956) and also the osteoporosis of the elderly (Valderrama and 

 Little, 1965). Although the detailed mechanism has been only partially elucidated, 

 anabolic agents have been used clinically to provide symtomatic relief, but practically 

 nothing has been reported which might suggest a mechanism of action. In the present 

 investigation rabbits were used as the experimental animal, and given cortisone alone, 

 or an anabolic agent alone, or various combinations of the two. "Stromba" (17/j- 

 hydroxy-17a-methylandrosteno(3.2-C)pyrazole) was the anabolic agent of choice as 

 it is reported to give a typical anabolic action with minimal side effects. 



