AMINO ACIDS IN PRE- AND POST-NATAL PERIODS 275 
c) Vitamins 
The hyperaminoaciduria of vitamin C deficiency was found by Jonxts!*° and has 
been confirmed by most of the other workers in the field™*: 187~189. In our own study, 
all ten children, even those demonstrating early prescurvy symptoms, showed an 
increased excretion of glutamic acid, aspartic acid, serine, threonine and some other 
acids. The plasma values of all the amino acids were within normal limits in such 
infants!8*, In scorbutic guinea-pigs RANGNEKER! found an increase of phenylalanine, 
lysine and histidine in blood. 
ARMBRUSTER?! claimed that vitamin C in relatively high doses (100 mg or more) 
causes an increase in the amino acid content of the urine (this publication is not 
well documented). A hyperaminoaciduria is also found in rickets, but not with the 
same regularity as with vitamin C deficiency!®®: 1,199, Only about half of our 49 
rickets cases have shown an elevated excretion rate. The plasma values were also 
found to be normal. JoNxis found an increased excretion of some amino acids in 
some blood relatives of children with rickets. This leads one to wonder whether 
peculiarities of tubular resorption of hereditary origin are responsible, in addition to 
the vitamin D deficiency, for this ricketsial hyperaminoaciduria. Vitamin E deficiency 
in rabbits also produced a hyperaminoaciduria?”. This is of some interest, since in 
human and animal progressive muscular dystrophy an increased excretion of some 
amino acids occasionally has been found’: 2°!~?°3. Vitamin A deficiency does not 
produce any significant change in the amino acid content of the serum or various 
organs of the rat?. A shortage of vitamin B, and pantothenic acid on the other hand 
is said to increase the level of arginine, methionine and tryptophane, whereas riboflavin 
deficiency leads to a higher level of valine in animals?®*. It is not clear whether the 
hyperaminoaciduria described by HANSEN et al. in infants deprived of pyridoxine 
is due only to the vitamin deficiency. Vitamin B,, deficiency according to GOKHALE 
AND PUNEKAR?® in rats produces a hyperaminoaciduria. 
3. Hormones 
Several hormones exhibit a significant influence on protein metabolism (cf. p. 267). 
The effect of glucocorticoides and ACTH on amino acid elimination by the kidney 
has been studied thoroughly, and found to produce a relatively intense hyperamino- 
aciduria?°®-09, A marked decrease in urinary amino acid elimination occurs after 
application of STH (ref. 210), as well as after effective doses of anabolic testosterone 
derivatives. As one might expect, insulin likewise produces a definite decrease in 
amino acid excretion. 
Central regulation is a field of amino acid metabolism which has hardly been studied. 
Better knowledge here would be valuable even for clinical purposes, since we have 
found that not only infants with well-known inborn errors of metabolism (e.g. 
phenylketonuria, maple-sirup-disease, etc.) but also children with common cerebral 
defects and mental retardation frequently show an increased amino acid excretion. 
In our material, of 50 cases 60°, had at least a slight increase and approx. 25°% a 
striking hyperaminoaciduria of the general type (see also refs. 211, 212). Two cases 
of so-called “myoclonus epilepsia” showed a very pronounced increase in almost all 
the usual amino acid found in urine. This instability of amino acid handling in 
cerebrally damaged children has a parallel in their difficulties with the regulation 
References p. 279/283 
