Acetone Metabolism 237 



CH2:C(OP03H2)COOH+HOH -> CH20HCH(OP03H2)COOH 



In addition to C2 and C^ cleavage the propanediol might be 

 oxidized to "pyruvate" or "lactate" and thus account for 

 the direct conversion of acetone to glycogen. 



Rudney prepared CHg-CHOH-^^CHgOH by reducing car- 

 boxyl labelled lactic acid. He tested this compound in rats, 

 using liver serine and liver glycogen as indicators (Rudney, 

 1950). The distribution patterns were as follows: — 



{^ f^ f^ (^ f^ f^ 



CH3 • CHOH • 14CH2OH 66 48 448 448 48 6% 



HOCH2 - CH(NH2) - COOH 

 CH3 • CHOH • i^HgOH 166 3 14 



In addition, the methvl carbons of the choline of the viscera 

 and liver were isolated and found to have 66 counts/min./mg. 

 C. The maximum activity in the respiratory CO 2 occurred 

 1 hour after the administration of the ^*C propanediol and 

 contained 500 counts/min./mg. C. 



It appears from these results that the propanediol is meta- 

 bolized very much as is acetone. It labels serine and choline, 

 and thus the indications are that a 1 -carbon compound is 

 formed from the hydroxymethyl carbon of propanediol. The 

 distribution of tracer in the glycogen is similar to that 

 obtained with acetone, in that the 1, 6 carbons are labelled 

 higher than the 2, 5 carbons, but differs in that the concen- 

 tration in the 3, 4 positions is higher relative to 1, 2, 5, 6 

 than was found with acetone. The high activity in the 3, 4 

 positions is probably indicative of direct conversion of the 

 propanediol as a 3-carbon unit to a carbohydrate precursor. 

 The activity of the respiratory CO 2 does not appear to have 

 been high enough to account for the activity in these positions 

 by CO 2 fixation. The relatively low activity in the 1, 2, 5, 6 

 positions as compared to that observed with ^^CHg • CO • ^^CHg 

 can be accounted for if it is recalled that i*CH3-CO-^*CH3 

 yields methyl labelled "pyruvate" by direct conversion and 

 methyl labelled "acetate" by C2 and Cj cleavage. Both of these 



