Table 2.
5 mm glucose, 10 nm insulin | 5 mm glucose, no insulin | 25 mm glucose, 10 nm insulin | 25 mm glucose, no insulin | |
---|---|---|---|---|
SAH hydrolase | ||||
Cytoplasm | 0.061 ± 0.017 | 0.076 ± 0.021 | 0.068 ± 0.017 | 0.084 ± 0.025 |
Membranes | ND | ND | ND | ND |
5′-Nucleotidase | ||||
Cytoplasm | 3.18 ± 0.42 | 3.16 ± 0.38 | 3.11 ± 0.41 | 3.07 ± 0.49 |
Membranes | 39.87 ± 4.12 | 37.38 ± 3.66 | 40.13 ± 4.84 | 33.91 ± 3.32 |
AMP deaminase | ||||
Cytoplasm | 1.65 ± 0.28 | 1.74 ± 0.32 | 2.81 ± 0.43*§ | 2.98 ± 0.51*§ |
Membranes | ND | ND | ND | ND |
Adenosine deaminase | ||||
Cytoplasm | 9.31 ± 1.25 | 8.21 ± 1.31 | 3.32 ± 0.61*§ | 2.94 ± 0.53*§ |
Membranes | 0.20 ± 0.03 | 0.60 ± 0.09* | 0.18 ± 0.03§ | 0.58 ± 0.07*† |
Adenosine kinase | ||||
Cytoplasm | 0.57 ± 0.16 | 0.63 ± 0.14 | 0.49 ± 0.17 | 0.53 ± 0.15 |
Membranes | ND | ND | ND | ND |
The data show enzyme activity (nmol min−1 mg−1). At ∼70% confluence, the culture medium was changed to Dulbecco's modified Eagle's medium containing 10% fetal bovine serum, glucose and insulin at concentrations as indicated. No insulin refers to a concentration of 10−11m. On the third day of culture, cells (1.5 × 107) were harvested and enzymes activities in cytosolic and membrane fraction were determined. The data represent the mean ± s.d. from four independent experiments.
P < 0.05 versus 5 mm glucose, 10 nm insulin
P < 0.05 versus 5 mm glucose, no insulin
P < 0.05 versus 25 mm glucose, 10 nm insulin. ND, not determined.