Hormones and Water and Electrolyte Metabolism 79 



and salt. There does not appear to be any inability to secrete 

 ADH or adrenocortical hormones, though it is possible that 

 the infant does lack the power to adjust the amounts secreted 

 with any precision. The endocrinological situation, therefore, 

 is essentially one of target-organ insensitivity due to im- 

 maturity. 



An interesting hypothesis relating to neonatal weight loss 

 has been put forward by Gans and Thompson (1957). These 

 workers measured the urine output and its content of oestro- 

 gens and 17-hydroxy corticosteroids in six normal male 

 neonates during the first few days of life. The findings were 

 similar in all the infants. Large amounts of oestriol (up to a 

 milligram or more) were excreted on the first post-partum 

 day, the quantity falling rapidly during the next two or 

 three days to the order of 1 or 2 [ig. by the sixth day. Oestrone 

 and oestradiol were found to the extent of 1-2 (xg. during the 

 first and second days and then disappeared. There was a 

 decreasing excretion of urine during the first three to five 

 days, and by the end of this time, postnatal weight loss had 

 ceased. The excretion of 17-hydroxy corticosteroids showed 

 only minor fluctuations throughout. The specific gravity of 

 the urine was low at first but became more concentrated as 

 the excess of water was excreted, in spite of the fact that 

 fluid intake was increasing during this time. 



Gans and Thompson suggest that part at least of the 

 hydraemia of the newborn infant is due to water retention 

 caused by the high circulating oestrogen level — the oestrogens 

 being, of course, of maternal origin. As the oestrogens are 

 excreted, the fluid excess is eliminated. 



Adrenal hyperplasia 



Adrenal hyperplasia is a disorder with a definite predi- 

 lection for the female sex. In Wilkins' series (Wilkins, 1957) 

 the ratio was 62 females to 19 males. The clinical manifesta- 

 tions of this disorder and its pathogenesis need not concern us 

 here. It is, however, relevant to observe that about one- 

 fourth of these patients have a tendency to loss of sodium and 



