METABOLISM 



Aneurine in Sweat 



Ordinarily, no appreciable quantities of aneurine are excreted in 

 the sweat, whether this is produced thermally or as the result of 

 exercise.*^ The sweat produced by exercise following the injection of 

 50 mg. of aneurine hydrochloride, however, contained a much greater 

 concentration (4-5 mg. per litre) than the urine excreted by the same 

 subjects (63 jug. per litre).*' 



Foetal Aneurine 



Aneurine appears to be incapable of passing the placenta, although 

 it accumulates in this organ, which thus serves to regulate the supply 

 of aneurine to the foetus.*® The concentrations of aneurine in the 

 venous and arterial blood of the umbilical cord were found to be 7-5 

 and 5 /xg. per 100 ml. respectively, compared with 2 to 12 fig. per 100 

 ml. in the maternal venous blood, and 27 to 10 /Ltg. per 100 g. in the 

 placenta. When 50 ftg. of aneurine hydrochloride were given intra- 

 venously before parturition, the aneurine contents of both the cord 

 blood and maternal blood and of the placenta increased, but the 

 injected aneurine disappeared rapidly except in the placenta. 



Aneurine only passes into the placenta when free,*^ although bound 

 aneurine is present in this organ in concentrations greater than that 

 of free aneurine ; the placenta contains 18 to 38 /xg. per 100 g. of 

 total aneurine, of which 4 to 8 fig. per 100 g. is in the free state. Oral 

 administration of aneurine to newborn babes resulted in its excretion 

 in the urine, but administration to the mother had little effect, because 

 it was stopped by the placental barrier. ^^ 



Aneurine Content of Milk 



The aneurine content of breast milk can be increased by increasing 

 the amount of aneurine in the diet, but only to a maximum of 25 to 

 32 /xg. per 100 ml. ^3' ^^ Breast-fed infants do not excrete aneurine, 

 and require less aneurine than do artificially fed infants.^^ According 

 to E. C. Slater and E. J. Rial,^^ breast milk contains about 9 /xg. of 

 aneurine per 100 ml. in the second week of lactation, rising to about 

 15 fjLg. per 100 ml. after twenty weeks and then gradually falling. Free 

 aneurine is maximal in the third or fourth week, but a large proportion 

 of the aneurine is present in phosphorylated form. Knott et al.,^^ 

 from an analysis of iii samples of milk from fifty women, record an 

 average concentration of 15 /xg. per 100 ml. None was present in the 

 colostrum but the concentration in the later milk increased gradually 

 to a maximum of 20 /xg. per 100 ml. in the first three weeks, thereafter 



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