Renin secretion from pre- and postconfluent As4.1 cells in the presence of FBS and IGF-I antibody measured by ELISA
| Pre-confluence | Postconfluence | |||
|---|---|---|---|---|
| + FBS (1) | – FBS (2) | + FBS (3) | + FBS + IGF-I antibody (4) | |
| Active renin (ng/well/h) | 7.2 ± 0.52 | 10.9 ± 0.31 |
17.9 ± 0.47 |
10.3 ± 0.34 |
| Inactive renin (ng/well/h) | 366 ± 112 | 245 ± 36.7 |
51.2 ± 16.0 |
242 ± 38 |
Values represent means ± SD from 6 wells. Cells were cultured to 70%–80% confluence in DMEM + 10% FBS (Pre-confluence) or to 100% confluence. Culture medium was replaced with DMEM without FBS (– FBS), DMEM + 10 % FBS (+ FBS), or DMEM + 10% FBS containing 10 ng/ml IGF-I antibody and cultured for 2 more days (Postconfluence). Cells were incubated in fresh media under each culture condition for 1 h to determine the rate of renin secretion. Levels of active and inactive renin were determined with the use of mouse renin ELISA kit from RayBiotech® and mouse prorenin kit from Molecular Innovations®, respectively. DMEM, Dulbecco’s modified eagle medium; FBS, fetal bovine serum; IGF-I, insulin-like growth factor-I. p-values were calculated by ANOVA. *p < 0.001 (1) vs. (2); **p < 0.001 (2) vs. (3); ***p < 0.001 (3) vs. (4); ****p < 0.001 (1) vs. (4); †p = 0.006 (1) vs. (2); ††p < 0.001 (2) vs. (3); †††p < 0.001 (3) vs. (4); ††††p = 0.005 (1) vs. (4). No significant difference between (2) and (4) in active and inactive renin secretion.