TABLE 2

Effects of glucose on the distribution of immunoreactivity to glucokinase, PFK-2, and GAPDH

Glucose-free medium
25 mmol/l glucose
GranulesMitochondriaGranulesMitochondria
Phogrin14.4 ± 2.2 (1.0)4.7 ± 1.0 (1.0)16.1 ± 4.5 (1.0)5.6 ± 0.4 (1.0)
Insulin30.6 ± 5.5 (2.1)7.1 ± 1.5 (1.5)34.9 ± 5.0 (2.2)6.8 ± 0.9 (1.2)
Glucokinase4.9 ± 1.7 (0.3)6.6 ± 1.3 (1.4)5.8 ± 0.9 (0.4)5.9 ± 0.9 (1.1)
PFK-217.8 ± 5.5 (1.2)10.3 ± 2.1 (2.2)17.4 ± 2.8 (1.1)12.5 ± 3.4 (2.2)
GAPDH4.6 ± 1.0 (0.3)2.7 ± 1.0 (0.6)4.0 ± 0.4 (0.3)2.3 ± 0.7 (0.4)
  • Data are means ± SE (recovery as a ratio to phogrin), n = 4–10. MIN6 were incubated for 2 h in glucose-free medium followed by 1 h without or with 25 mmol/l glucose. The cells were homogenized and the organelles fractionated on a Percoll gradient, as in Fig. 3. Immunoreactivity in the percoll fractions corresponding to the insulin granules or the mitochondria is expressed as percentage of total immunoreactivity loaded on the gradient.