230 



PHYSIOLOGICAL EEGULATIONS 



+2 +4 +6 



Water Load 

 Fig. 129. Eenal (urinary) clearance from plasma of creatinine, inulin, and urea 

 (% of Bo/hour) in relation to sensible water load (% of Bo). Dog. The urea clear- 

 ance was transformed, by means of figure 26, from a relation to rate of urinary water 

 excretion as averaged in data of Dominguez ( '35, p. 537) to an approximate relation to 

 water load. The ratio of creatinine clearance to urea clearance was then taken from 

 Shannon ( '36b, p. 210), and of inulin clearance from Shannon ( '35 and '36a). 



phorus, and some of the other materials with water excesses, as 

 noted in § 83. 



An actual example of the effects of water excretion upon urea 

 content may be taken from data of Greene and Rowntree ('27). 

 Dog 183 weighed 7.0 kg. ; taking 66 per cent of this as the volume 

 of distribution (Painter, '40) of urea, which was 6 mM in whole 

 blood, some 28 millimols were present in the body initially. This 

 dog may have formed 9.3 millimols of urea per hour. If the rate 

 of urea formation and the volume of distribution be constant, but 

 the clearance of urea be augmented, almost doubled at times, during 



TABLE 25 



Computation of extra urinary elimination of urea that might occur during maintained 

 water excess in which urea clearance is doubled. Dog 



