The influence of age and chronic restricted feeding on protein synthesis in the small intestine of the rat.
Rates of protein synthesis (measured in vivo) and growth of the small intestine were studied as a function of age in ad libitum fed (control) and chronic dietary-restricted rats. At weaning, the fractional rates of synthesis in the mucosal and muscularis externa and serosal layers of the small intestine of control animals were similarly high (90-100% per day). Although these rates subsequently declined with age in the muscularis externa and serosa, they remained constant in the mucosa. Restricted feeding (50% reduced intake), when imposed from weaning onwards, significantly extends the maximum life span of rodents. However, the change in nutritional status slows the accumulation of protein, RNA, and DNA in both layers of the small intestine. Although underfeeding did not prevent the age-related fall in muscularis externa and serosal protein synthesis, significantly higher rates (both fractional and per ribosome) were found when compared age for age with controls. Mucosal fractional synthetic rates were similarly increased by the reduced food intake. These changes in protein turnover in the small intestine are consistent with the higher rates of whole body turnover previously observed in chronically underfed rats.
Merry
B J
BJ
Institute of Human Ageing, University of Liverpool, UK.
Lewis
S E
SE
Goldspink
D F
DF
D000375:Aging / Q000502:physiology*; D000818:Animals; D004247:DNA / Q000096:biosynthesis; D004038:Diet, Reducing; D007413:Intestinal Mucosa / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism*; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains
D012313:RNA; D004247:DNA