Glucose turnover in the young chicken (Gallus domesticus) using variously labeled (³H, U-¹⁴C) glucose tracers

1. 1. Various parameters of glucose metabolism-glucose replacement rate, percent recycling, mean transit time, and glucose mass were examined using various double labeled glucose tracers-2T-, U-¹⁴C; 3T-, U-¹⁴C; 4T-, U-¹⁴C; 5T-, U¹⁴C; and 6T-, U-¹⁴C. 2. 2. Estimates of replacement rate were greatest for 2T-glucose (21.4 mg/min/kg), with 3T-, 4T-, 5T-, and 6T-glucose all having similar values (15.8, 15.6, 17.0, 16.0 mg/min/kg, respectively). 3. 3. Calculated glucose mass based on all tritiated tracers (734-1086 mg/kg body weight) agreed closely with a direct determination of body glucose (969 mg/kg). 4. 4. Reincorporation of tritium from ³H₂O into glucose did not occur to any significant degree. 5. 5. The young chick was found to have a very rapid rate of glucose turnover and high percent recycling compared to mammals.