Table 3.

Mixed linear regression model estimates for ACTH concentrations (ng/ml) measured in diluted medium samples from cells transfected with KCNQ1 and KCNE2

Parameter	Estimate	SE	P
Intercept (WT KCNQ1/KCNE2)a	9.59	0.84	<0.001
Time	0.62	0.15	<0.001
KCNQ1-Arg116Leu/KCNE2	−1.88	0.42	<0.001
KCNQ1-Pro369Leu/KCNE2	−1.29	0.42	0.004
KCNQ1-Gly589Asp/KCNE2	−0.77	0.42	0.075

Mixed linear regression model estimates for ACTH concentrations (ng/ml) measured in diluted medium samples (1:10) in the reference condition (WT KCNQ1/KCNE2) and three other KCNQ1 conditions (KCNQ1-Arg116Leu/KCNE2, KCNQ1-Pro369Leu/KCNE2, KCNQ1-Gly589Asp/KCNE2), their standard errors (SE), and corresponding P values. The model included both the growth time (per 1 h) and the KCNQ1/KCNE2 conditions as fixed effects and the experiment number as a random intercept. Based on the regression model, the KCNQ1-Arg116Leu with KCNE2 produced 20% (−2 h) or 17% (0 h) less ACTH than the reference (WT KCNQ1 with KCNE2) (P < 0.001). Similarly, the KCNQ1-Pro369Leu with KCNE2 produced approximately ~12–13% less ACTH (P = 0.004) than the reference environment. ACTH levels produced by the cells transfected with the LQT1 mutant KCNQ1-Gly589Asp/KCNE2, which served as a control, did not differ significantly from the reference environment. The CRF-induced ACTH responses between the four KCNQ1/KCNE2 conditions did not differ (data not shown)

^aAt −2 h