Changes in the Rates of Recycling and Turnover of Glucose during Development of Sheep

The rates of recycling and turnover of glucose in 5-day- and 21-day-old lambs and adult sheep were measured by the method of single simultaneous injection of glucose-6-3H and glucose-6-14C. The 3H/14C ratio decreased linearly with time and was 0.58 and 0.60 in lambs of 5-day- and 21-day-old, respectively, and 0.82 in adult sheep at 120 min after injection of the labeled glucose. The pool size and turnover rate of glucose considerably decreased with age. The rate of glucose recycling was significantly higher in lambs of both ages (22.0 and 26.2%, respectively) than in adult sheep (11.1 %).