TRIGLYCERIDES AND FATTY ACIDS 157 



ketonuria were produced. One interesting fact which was recorded was 

 the al)sence of any increase in the level of ketonuria on fasting. 



Man has been shown to exhibit the greatest sex difference in starvation 

 ketosis. Thus, Deuel and Gulick-'^^ found that the average ketone body- 

 excretion, when based upon surface area, was approximately four times as 

 great in women as in men. The sex difference in the excretion of ketone 

 bodies over a four-day period is illustrated in Figure 1. 



(d) Type of Food Ingested as a Factor in Ketonuria. It has long been 

 known that the type of food ingested affects the extent of ketonuria during 

 the period when any particular regimen is being consumed, and subsequently 

 during a period of fasting. Thus, a protein-fat diet largely free from car- 

 bohydrate caused a persistent ketonuria over a period of a year in the 

 case of two Arctic explorers studied by McClellan and DuBois.^^^ When 

 extra fat is added to a diet lacking in carbohydrate, the extent of ketonuria 

 is exaggerated.^*^'*^^'^^ The increased ketonuria occurs concomitantly 

 with a decreased nitrogen excretion. On the other hand, a reduction of fat 

 in the ketogenic diet was shown by Salomonsen^** to increase the protein 

 loss as indicated by an increased urinary nitrogen. 



The extent of ketosis occurring during the period of alimentation is 

 also influenced by the caloric intake. Thus, it has been repeatedly demon- 

 strated that the onset of acetonemia in cattle, and in pregnancy disease in 

 ewes, almost invariably occurs when the level of food intake is considerably 

 below the required amount. The reader is referred to the earlier section 

 on species as a factor in ketonuria for a further exposition of this point (see 

 page 146). 



Finally, Deuel et al. ^^^ reported that, following a low-protein, low-choline 

 diet such as to induce the development of fatty livers, rats excreted a high 

 level of ketone bodies on subsequent fasting. It is believed that ketonuria 

 occurs during fasting following this deficient diet because of the stimulation 

 of fat breakdown due to the high level of this foodstuff in the liver. Some 

 justification for this viewpoint was furnished by the fact that the rate of 

 decrease of liver lipid in the female rats during fasting was greater than that 

 in males; this finding was consistent with a higher endogenous ketonuria 

 in female rats than was observed in males. 



MacKay et a/.^^^ challenged the viewpoint that the level of liver fat is 

 the deciding factor in effecting the ketosis. Thus, they were unable to 



«' G. Becker, Acta Med. Scand., 63, 313-335 (1926). 

 ^68 L. Salomonsen, Ada Paediat., 9, Suppl. I, 1-146 (1929-1930). 

 «« E. M. MacKay, H. O. Carne, A. N. Wick, and F. E. Visscher, J. Biol. Chem., HI, 

 889-896 (1941). 



