Glutamine metabolism is changed in lymphocytes from aged rats.
Changes in the protein content, maximal activity, and Km of phosphate-dependent glutaminase were measured in the lymphoid organs (thymus, spleen, and mesenteric lymph nodes) from just-weaned, mature (3 months), and aged rats (15 months). Also, [U-14C] glutamine transport and decarboxylation and the production of glutamate and aspartate from 2 and 20 mM glutamine were measured in incubated mesenteric lymph node lymphocytes. The ageing process induced a reduction in the protein content of the thymus and spleen, as well as the phosphate-dependent glutaminase activity in the thymus and isolated lymphocytes. The Km of phosphate-dependent glutaminase, however, was not affected by the process. Ageing reduced [U-14C] glutamine decarboxylation and increased glutamate and aspartate production in incubated lymphocytes. The results indicate that the ageing process does modify several aspects of glutamine metabolism in lymphocytes: reduces maximal glutaminase activity and [U-14C] glutamine decarboxylation and increases the Km for [U-14C] glutamine uptake and the production of glutamate and aspartate.
Almeida
A F
AF
Department of Physiology and Biophysics, University of São Paulo, Butantan, Brazil.
Costa Rosa
L F
LF
Curi
R
R
D000375:Aging / Q000378:metabolism*; D000818:Animals; D018698:Glutamic Acid / Q000378:metabolism*; D008198:Lymph Nodes / Q000378:metabolism*; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D051381:Rats; D013154:Spleen / Q000378:metabolism; D013950:Thymus Gland / Q000378:metabolism
D018698:Glutamic Acid