ASSESSING HIGH DIETARY VITAMIN A

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. To further define the effects of chronically high dietary vitamin A. Recent work examining the vitamin A (VA) status of rhesus monkeys (Macaca mulatta) used as models for human biomedical research revealed subtoxic hepatic VA concentrations. Marmoset monkeys (Callithrix jacchus), also showed high VA levels and high serum retinyl ester concentration. Both species consumed common research diets that provided up to four times the amount of VA recommended by the National Research Council. Further interpretation of these findings is limited to tissue retinol and retinyl ester profiles and extrapolation from other species rather than direct comparison to normal values. To further define VA status in rhesus monkeys, male rhesus monkeys were used for a study that involved stable isotopes and liver biopsies. While the VA analysis is still in process, we found ¿abnormal¿ values in the chemistry screening profiles in 10 of the 16 male rhesus monkeys (age range 8 to 15 years). Among the monkeys, these included elevated alkaline phosphatase, gamma-glutamyl transferase, lactate dehydrogenase, and aspartate aminotransferase. Elevations of these enzymes are cause for concern as they are all markers of liver disease or malfunction, which is a direct outcome of vitamin A toxicity. This research used WNPRC Research Services.