90 G. I. M. SwYER 



co-workers (1956) to cause a fall in urinary aldosterone 

 excretion in normal persons. In the pre-eclamptic patients 

 studied by Rinsler and Rigby (1957), the aldosterone outputs 

 were considerably less than those at the same stage of normal 

 pregnancy and it was concluded that this was because of the 

 expanded ECF compartment. The output of aldosterone in 

 these toxaemic patients is less, for a given urinary Na/K 

 ratio, than in the normal group; yet despite the low aldo- 

 sterone output, sodium retention is maintained or increased. 

 This suggests that a mechanism other than that of aldo- 

 sterone secretion may be responsible for the sodium retention 

 of pre-eclamptic toxaemia. 



Labour, especially if prolonged, is another aspect of 

 pregnancy in which electrolyte disturbance may assume im- 

 portance. Hawkins and Nixon (1957) have demonstrated a 

 consistent loss of plasma water and increase in plasma specific 

 gravity after only 20 hours of labour, indicating a state of 

 dehydration long before the appearance of clinical signs. In 

 addition, they found an increase in plasma sodium and a 

 decrease in chloride and potassium. This, they suggest, is due 

 to increased renal excretion of chlorides necessitated by the 

 disturbance of acid-base balance due to ketosis resulting from 

 shortage of available glycogen. After 48 hours of labour, a 

 striking fall in plasma potassium and in circulating eosinophils 

 was seen. This is consistent with increased adrenocortical 

 activity, such as is known to occur after surgical operations 

 (MacPhee, 1953). In labour, this fall in plasma potassium 

 may be particularly important because of its influence on 

 uterine contraction. It is very probable that potassium 

 depletion in long labours materially adds to the inefficiency 

 of an already inert uterus. 



Changes in Steroid Metabolism in Ageing Men and 

 Women 



The most extensive study of this subject has been made by 

 the Worcester group (Pincus et al., 1955). Certain of their 



