/. /; 17 /.0,S7v ( Fh'CCTOSE ) 655 



fully (liahctic <iiiiiii;il it is c-apiihlc (if l)('iii<i: coiivcrlcd (iiiiiiililat i\cl\' 

 into {i'lucosc. h].\istiiijr data imlicalc that j^alaetoso, like diusi- and 

 ji'lycoiMC aldi^liydc, is ciiiefly convcrtt'd into itlufosc bcfoi'c fiirllirr nlil- 

 ization, and that this pi'occss is carried out niaiidy in tlic li\cr and 

 howcl wall. The litci'atni'c of the sulijcci is <:iv('n hchiw.'" 



LEVULOSE (FRUCTOSE) 



The uroup of ci^ht sugars formed by levulose in the presence of 

 alkali includes glucose, and any member of this group will produce 

 all the others. Then, in cases of glycosuria with alkaline urine 

 (whether physiological or due to medication or to bacterial decompo- 

 sition), levulose might be expected to occur along with glucose. May 

 and Koenigsf eld have reported instances of this ' ' urinogenous levu- 

 losuria. " However, since the OH concentration of fresh urine seldom 

 or never attains a height sufficient to turn phenolphthalein red, Mag- 

 nus-Levy doubts the correctness of these observations. 



Alimentary Levulosuria. — The tolerance of a normal body for levu- 

 lose given per os is variable. Doses of 50 to 70 gm. in man cause a.s a 

 rule no levulosuria, but more is likely to do so. Animals in wiiich 

 the liver parenchyma has been damaged by phosphorus are said to 

 have a lower tolerance. In many other diseases of the liver the same 

 holds true, and IT. Strauss believed this fact could be made the basis 

 of a clinical test for liver function. Naunyn, however, emphasi;^es 

 the fact that in certain cases of cirrhosis of the liver with collateral 

 anastomoses between the portal vein and vena cava, there is also a 

 lessened tolerance for levulose given by mouth, owing to the fact that 

 levulose then enters the general circulation without having entered 

 the liver. As far back as 1871 Eichhorst showed that levulose intro- 

 duced per rectum, i. e., where it will presumably enter an hemor- 

 rhoidal vein after resorption, is more likely to cause alimentary 

 levulosuria than when swallowed, because of the extra-hepatic an- 

 astomoses between the hemorrhoidal veins and the vena cava. As in 

 the case of diose, glyceric aldehyde and galactose, intravenous injection 

 of levulose produces levulosuria in dogs when tlie rate of injection is 

 between 0.1 and 0.2 gram per kilo per hour. These facts support the 

 belief that the liver plays the same inipoi-tant i>art in "assimilating" 

 levulose as with other sugars. 



Spontaneons Alimeniarj) LcvuJosuria, i. c, the appearance of lev- 

 ulose in the urine from such small quantities of levulose as occur 

 naturally in the food, has been demonstrated in eight cases. In five 

 of these levulose apjiears to have been the only sugar present. These 

 persons showed a decreased tolerance for ingested levulose and ceased 

 passing the sugar when the diet was cai-bohydrate-free. The tend- 



31 Bauer, Dent. nied. Wocli.. IftdS (.3.)), 150."): Roiss u. .Tohn, Dcut. Arcli. f. 

 klin. Med., 1012 (108), 1S7: Roiibitscheck, Dcut. Areli. f. klin. Mod., 1012 (108), 

 225; Naiuiyn, "Bcitriifio 7,ur Lchre von Ikterus, etc.", Reichcrt-Duboisschcs Archiv 

 fiir Anatomie, 18G0, p. 570; Schupffer, Arch. f. exp. Path. u. Pharm, 1873 (1), 73. 



