Rates of pyruvate utilization and lactate formation by lymphocytes from young and aged rats

The rates of pyruvate utilization and lactate formation were measured in lymphocytes from young (newly weaned), adult (3-month old) and aged (15-month old) rats. Lymphocytes obtained from mesenteric lymph nodes were incubated at 37 degrees C for 1 h. The conversion of pyruvate to lactate accounted for 92.5% of the total pyruvate utilized by lymphocytes from young rats and was 34.2% and 44.5% for adult and aged rats, respectively. When lymphocytes were stimulated with concanavalin A there was an increase of 65.6% and 37.1% in the rates of pyruvate utilization by lymphocytes from young and adult rats, respectively. No changes in pyruvate utilization were observed in response to concanavalin A in lymphocytes from aged rats.