Monkey ascorbic acid metabolism

Studies on the excretion of 17-ketosteroids by female rats on a diet deficient in pantothenate have not been reported. These data would be interesting because of the observations of Dorfman (1947), who reported a sharp decrease in the excretion of 17-ketosteroids in female monkeys and guinea pigs following adrenalectomy. It was also observed that in the scorbutic female guinea pig (Dorfman, 1947 Banerjee and Deb, 1952) there was a sharp decrease in the excretion of 17-ketosteroids. These observations indicate that the adrenal is the source of these steroids and that diets deficient in ascorbic acid, which affects the adrenals, will also decrease the synthesis of these steroids. In view of the fact that there is a disturbance of ascorbic acid metabolism in pantothenate-deficient rats, it may well be that this would contribute to a disturbance in the synthesis of the 17-ketosteroids in the pantothenate deficiency. 

A DHA lactonase has been described (76,77) in the ox, rabbit, rat, and guinea pig. In the ox the lactonase is present in several tissues but is most abundant in the liver. The enzyme appears to be absent in human and monkey tissue. This result is consistent with the observation that primates and fishes do not catabolize labeled ascorbic acid to carbon dioxide. AA and DHA appear to be metabolized into a series of water soluble products that are excreted in the urine, but 2,3-DKG is decar-boxylated and otherwise degraded to intermediates that enter the C5 and C4 carbohydrate pools (78). 

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