Figure 2.

Effect of insulin and oxygen on mRNA expression of serotonin-regulating genes in ACH-3P cells. Cells were cultured in the absence (control, grey bars) or presence of 10 nM insulin (hyperinsulinemia, orange bars) at 6.5% O₂ or 2.5% O₂ for 24 h or 48 h. Relative mRNA expression levels of (a) SERT, (b) TPH1 and (c) MAOA were determined by RT-qPCR and normalized to YWHAZ mRNA level. Results of three independent experiments, each done in duplicate or triplicate, are shown. For each gene, data are presented relative to the mean of the control sample at 6.5% O₂, which was arbitrarily set to 1.0; bars represent mean ± SEM. Statistical analysis used ANCOVA with cell passage as covariate and Sidak’s test to adjust for multiple comparisons. * p < 0.05, orange dashed line—main effect of insulin. ^# proportion of total variance after controlling for the effect of the cell passage (partial η²).