Progesterone block of the human α4β2 receptor in the absence and presence of β-estradiol indicates a lack of competition
| No β-estradiol | +3 μm βE2 | +15 μm βE2 | |
|---|---|---|---|
| 3 μmPROG | 0.37 ± 0.13 (n = 7) | 0.22 ± 0.05 (n = 4) | 0.25 ± 0.03 (n = 4) |
| 15 μm PROG | 0.10 ± 0.04 (n = 4) | 0.08 ± 0.04 (n = 7) | 0.05 ± 0.01 (n = 3) |
βE2 refers to 17β-estradiol. PROG (3 or 15 μm) was pre-applied for 20 sec before a test pulse containing 1 μm ACh plus the concentration of PROG that was pre-applied plus 0, 3, or 15 μm βE2. The table shows the relative response in the presence of PROG (3 or 15 μm) to the response in the absence of PROG: the first data column is normalized to 1 μm ACh (no βE2); the second column is normalized to 1 μm ACh plus 3 μm βE2; and the third column is normalized to 1 μm ACh plus 15 μm βE2. The SD follows and the n value is shown in parentheses.