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Fig. 3. Effects of Ca2+, calmidazolium, ML-7, isoproterenol and forskolin on active renin secretion in postconfluent As4.1 cells. Cells on day 2 postconfluence were incubated in Ca2+-free DMEM containing 1 mM EGTA (–Ca2+ DMEM) (A, left panel) and then in 2 mM Ca2+-containing DMEM and 10% FBS (+Ca2+ DMEM) successively for 1 h each or in the reverse order (A, right panel, p < 0.001, n = 6). In the next series of experiments, cells were incubated in +Ca2+ DMEM for 1 h (control) and then another 1 h in +Ca2+ DMEM + 10 % FBS containing either calmidazolium (3 × 10−5 M) (B, n = 6), ML-7 (6 × 10−5M) (C, n = 6), isoproterenol (10−8–10−5 M) (D, n = 6) or forskolin (3 × 10−5 M) plus IBMX (10−4 M) (E, n = 6). The rate of active renin secretion was determined by radioimmunoassay for ANG I in (A) and (B) or by ELISA in (C), (D), and (E). ANG I, angiotensin I; DMEM, Dulbecco’s modified eagle medium; FBS, fetal bovine serum. Samples within groups were compared using paired Student’s t-tests and between groups using unpaired Student’s t-tests (A–C, E) or ANOVA (D), *p < 0.001 vs. control, except between samples at the two highest concentrations, which were compared by unpaired Student’s t-tests. p < 0.001.
Korean J Physiol Pharmacol 2022;26:479-499
© Korean J Physiol Pharmacol