Monkeys, ascorbic acid requirement

Recently, workers using serum ascorbic acid values as the reference of their estimation of ascorbic acid requirements in monkeys and baboons found that captivity and handling increased the ascorbic acid requirements (51,52). They concluded that captive monkeys required 20 mg of ascorbic acid/d in addition to fruit supplements. No differences were measured in the response of serum ascorbic acid after supplementations of 5 or 10 mg of ascorbic acid/kg of body weight/d in the baboon. 

Other investigators have found larger amounts of ascorbic acid were necessary to maintain normal concentrations of the vitamin in blood. For monkeys, 10 (63) and 25 (35) mg of ascorbic acid/kg of body weight were proposed as the minimum required amounts. Recent experiments showed that the trained monkey required only 3-6 mg of ascorbate/kg of body weight (120). Young monkeys (sexually imma-... 

The rat is a poor choice to evaluate the liver injury potential of a substance for man, because the rat liver is resistant, and regenerates rapidly. The guinea pig or the rabbit would be a better choice of this. The dog does not acetylate or detoxify aromatic amines. The monkey and the guinea pig require exogenous ascorbic acid, while the rat does not, which makes the rat unsuitable for the demonstration of an ascorbic and deficiency. 

Vitamins are any organic dietary substance necessary for life, health, and growth that do not function by supplying energy. They usually function as coenzymes. Vitamins for one species may not be vitamins for another. Only humans, monkeys, and guinea pigs lack the ability to synthesize ascorbic acid (vitamin C), for instance. Indeed, bacteria in the gut synthesize some essential vitamins, which are absorbed in amounts sufficient to meet daily requirements. The administration of antibiotics for a long period of time could thus result in a vitamin deficiency of the bacterial host. 

Bums, J. J., 1957, Missing step in man, monkey and guinea pig required for the biosynthesis of L-ascorbic acid. Nature 180 553. 

May et al. (1950a,b, 1951) originally considered that ascorbic acid was necessary for the conversion of pteroylglutamic acid to citrovorum factor. In monkeys fed on diets deficient both in ascorbic acid and folic acid, megaloblastic anemia developed. This could be relieved by ascorbic acid, by folic acid in large doses, or by small doses of citrovorum factor. Later May et al. (1953) reported that ascorbic acid was not required for the conversion of folic acid to citrovorum factor. The severe deficiency of folic acid compounds occurring in scorbutic monkeys was probably due to nonspecific factors operating in scurvy. 

Vitamin C—also called ascorbic acid, dehydroascorbic acid, hexuronic acid, and the antiscorbutic vitamin—is the very important substance, first found in citrus fruits, which prevents scurvy, one of the oldest scourges of mankind. All animal species appear to require vitamin C, but a dietary need is limited to humans, guinea pigs, monkeys, bats, certain fish, and perhaps certain reptiles. These species lack the enzyme L-gulonolactone oxidase which is necessary for vitamin C synthesis from 6-carbon sugars. 

The minimal daily requirement to prevent any possible prescorbutic condition in man is about 19-25 mg. ascorbic acid, the advisable intake for a 70 kg. subject being about 60 mg., or nearly 1 mg. per kg. body -weight. The requirements of a child are about twice as much. Many animals, notably the rat, are immune from scurvy, and presumably can synthesise the vitamin. Man, the monkey, and the guinea pig, are entirely dependent on exogenous sources. 

The only species known definitely to require a dtetary source of vitamin C are man, monkeys and guinea pigs. It is possible that in mice, rabbits, swine and cattle vitamin C is required under certain conditions (45). A report by Philipps, et al. (133) indicates that dietary ascorbic acid is necessary for reproduction of cattle. These authors found that cows which had failed to reproduce conceived after injections of ascorbic acid. 

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