title: Utilization of 14C-tyrosine in brain and peripheral tissues of developmentally protein malnourished rats.
abstract: Prior studies of developmentally protein malnourished rats have reported substantial changes in brain and peripheral utilization of 14C-leucine, 14C-phenylalanine, and 14C-tryptophan. In the present study rats born to dams fed a low protein diet (8% casein) compared to the offspring of control rats fed a normal diet (25% casein) showed few significant differences in the uptake and incorporation of 14C-tyrosine into brain and peripheral tissues from birth to age 21 days. At birth, the 8% casein pups exhibited significant decreases in brain and peripheral tissue incorporation of tracer only at short post-injection times (10 and 20 min), but not at longer intervals (90 and 180 min). During ontogenetic development (Days 5-21), the 8% casein rats showed significant increases in uptake of 14C-tyrosine into the brain and peripheral tissues on Day 11 and a significantly higher percent incorporation of tracer into brain protein on Day 21 as compared to the 25% casein rats. For the most part, there were no significant changes in incorporation of radioactivity in peripheral tissues for the 2 diet groups on these post-birth days. Overall, the data indicates that developmental protein malnutrition causes relatively fewer changes in brain and peripheral utilization of the semi-essential amino acid tyrosine than those observed in previous studies with essential amino acids.
mesh_terms: D000818:Animals; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D002250:Carbon Radioisotopes; D004044:Dietary Proteins / Q000378:metabolism*; D005260:Female; D009748:Nutrition Disorders / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D002250:Carbon Radioisotopes; D004044:Dietary Proteins; D011506:Proteins; D014443:Tyrosine