Ascorbate metabolism in the trained monkey.

The metabolic fate of 14C-1-ascorbate was studied in trained monkeys (Macacca fasicularis) by measurement of the 14C in the expired breath, urine, and feces. To minimize stress, each monkey was placed in a restraining primate chair and trained to all experimental procedures prior to the isotope studies. The majority of the 14C-1-ascorbate was absorbed by the trained monkeys and ascorbate turnover increased with increasing plasma levels. The urine of trained monkeys was the major excretion route of 14C-1-ascorbate and its metabolites. less than 2.5% of the 14C-1-ascorbate was oxidized in 24 hr to 14CO2. The 14CO2 production was not changed by diet or the ascorbate nutritional status in the trained monkey. A significant increase in 14CO2 production was measured in an untrained monkey. The metabolic fate of 14C-1-ascorbate in man and the trained monkey was similar. Therefore, the trained monkey could be a study model for ascorbate metabolism in man.