Burst Component Colonies Produced In Vitro by Normal and PV Erythroid Progenitor Cells With Increasing Amounts of IGFBP-1 in the Presence of IGF-I
| IGF-I (mol/L) | 3 × 10−11 | 3 × 10−11 | 3 × 10−11 | 3 × 10−11 | 3 × 10−11 |
| IGFBP-1 (mol/L) | 0 | 3 × 10−14 | 3 × 10−13 | 3 × 10−12 | 3 × 10−11 |
| Normal | 89 ± 7.2 | 84 ± 7.8 | 101 ± 8.0 | 164 ± 4.7 | 166 ± 12.8 |
| Normal | 72 ± 3.3 | 92 ± 8.8 | 107 ± 5.0 | 244 ± 24.6 | 209 ± 25.4 |
| PV | 134 ± 3.3 | 207 ± 13.4 | 214 ± 4.7 | 247 ± 10.0 | 228 ± 27.0 |
| PV | 29 ± 2.0 | 39 ± 3.4 | 61 ± 7.1 | 74 ± 5.0 | 88 ± 4.8 |
| PV | 202 ± 13.4 | 218 ± 9.0 | 186 ± 11.3 | 318 ± 9.6 | 280 ± 15.0 |
| IGF-I (mol/L) | 3 × 10−11 | 3 × 10−11 | 3 × 10−11 | 3 × 10−11 | 3 × 10−11 |
| IGFBP-1 (mol/L) | 0 | 3 × 10−14 | 3 × 10−13 | 3 × 10−12 | 3 × 10−11 |
| Normal | 89 ± 7.2 | 84 ± 7.8 | 101 ± 8.0 | 164 ± 4.7 | 166 ± 12.8 |
| Normal | 72 ± 3.3 | 92 ± 8.8 | 107 ± 5.0 | 244 ± 24.6 | 209 ± 25.4 |
| PV | 134 ± 3.3 | 207 ± 13.4 | 214 ± 4.7 | 247 ± 10.0 | 228 ± 27.0 |
| PV | 29 ± 2.0 | 39 ± 3.4 | 61 ± 7.1 | 74 ± 5.0 | 88 ± 4.8 |
| PV | 202 ± 13.4 | 218 ± 9.0 | 186 ± 11.3 | 318 ± 9.6 | 280 ± 15.0 |
Data from titrations of IGFBP-1 in the presence of 3 × 10−11 mol/L IGF-I with respect to erythroid burst formation by PV and normal progenitor cells in vitro. Data for cells of 2 normal individuals and 3 PV patients are given as the mean number of burst component colonies ± the standard error of the mean and were used to plot the curve shown in Fig 5.