52 



K. J. Franklin 



The Unit's second research study was upon the renal blood 

 content, and its variations with age, in the rabbit; in this 

 study, Lindop (1956) made one of the earlier uses of radioactive 

 isotopes in studies of ageing, summarized as follows: 50 

 rabbits of a standard strain, aged from 1 day to 3 years, were 

 found to have renal blood contents (ml./lOO g. renal tissue) 

 ranging from 50 neonatal to 41 between weaning and puberty, 

 and thereafter to 30 in adult life. These levels are the result- 

 ants of all stimuli acting together under the conditions 



80 



60 



PERCENTAGE 

 CAPACITY 

 RESPONSE 



40 



20 



AGE IN YEARS 



Fig. 3. Diagram showing percentage capacity to reduce renal blood content 

 at different ages. Subjects : 50 Rahere rabbits. 



obtaining. The standard extra stimulus in each case was a 

 period of 20 sec. asphyxia of the whole animal (Franklin, 

 McGee and Ullmann, 1951), such asphyxia being permitted to 

 act reflexly upon one kidney only. It caused a drop in renal 

 blood content to 20 ± 4, irrespective of age, so the actual 

 drop decreased with age from neonatal to adult (Fig. 3). 



The third research, also by Lindop, is a study of thyroid 

 function, and in it she has once again used radioisotopes for 

 the physiological, non-structural assessment of function. 

 Tracer doses of radioiodine have been used in rats to study 



