title: Protein malnutrition in aged rats: an experimental model.
abstract: Although protein requirements have been shown to decrease in rats with age, very few studies have dealth with old animals. In addition, a model of protein deficiency in aged rats has not been established. Nineteen-month-old male Sprague-Dawley rats were fed a 25 (control), 5, or 3.5% casein diet for 1 week ad libitum. Liver protein and RNA content were reduced in the 3.5% casein group when compared to controls. No differences were observed between the control and the 5% casein group. Also, no differences were observed in incorporation of [14C]orotic acid into liver nuclear RNA between these two groups. However, this variable was significantly higher in the 3.5% casein group when compared to control. When comparing the results of this study with our previous studies in young adult rats, the 3.5% casein diet produced biochemical changes in liver that are qualitatively and quantitatively similar to the ones observed in young adult rats fed a 6% casein diet ad libitum, which allows a more direct comparison of the effect of protein deficiency on the aged rat.
mesh_terms: D000375:Aging; D000818:Animals; D001835:Body Weight; D002364:Caseins / Q000008:administration & dosage; D004247:DNA / Q000378:metabolism; D004032:Diet; D004195:Disease Models, Animal; D008099:Liver / Q000378:metabolism; D008297:Male; D009929:Organ Size; D011488:Protein Deficiency / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002364:Caseins; D011506:Proteins; D012313:RNA; D004247:DNA