Ascorbic Acid Deficiency in the Squirrel Monkey ∗

Abstract

Evidence that primates require exogenous ascorbic acid has not been established for all species. The general statement that monkeys require exogenous vitamin C is based in large part on evidence for such a need in the rhesus monkey, Macaca mulatto, (1). A requirement for exogenous ascorbic acid has also been reported for Cebus fatuellus (2), Macaca cyclopsis swinhoi (1), and Cercopithecus aethiops (3). Elliot et al. (4) reported that liver slices of the prosimian primates, Tupaia glis and Nycticebus coucang, can synthesize ascorbic acid from gulonolactone in vitro, and presumably do not require an exogenous source of this vitamin. Chatterjee et al. (5), however, have noted that D-glucurono reductase, which converts D-glucuronolactone to L-gulonolactone, is specifically absent in those species which cannot synthesize L-ascorbic acid. If these prosimians can make the conversion of D-glucuronolactone to L-gulonolactone they presumably would not require an exogenous source of this vitamin. The present study was done to determine whether the squirrel monkey, Saimiri sciureus, requires an exogenous source of ascorbic acid.

Materials and Methods. Six juvenile Brazilian squirrel monkeys, obtained from Leticia, Colombia were used in this study. The monkeys were fed a diet devoid of ascorbic acid (Table I). After 3 months on the ascorbic acid free regimen, 3 of the animals were supplemented with ascorbic acid at a level of 10 mg/kg of body weight per day. The ascorbic acid was given intramuscularly as an aqueous solution, prepared just prior to administration. The remainder of the animals were continued on the ascorbic acid free regimen for the 4-month period of study. Body weighty packed cell volume, and serum ascorbic acid were examined at monthly intervals. Serum ascorbic acid was determined by titration of the serum with dichlorophenolindophenol (6).