GH-activated STAT5 induces Cyp7b1 DHS chromatin opening but not Cyp7b1 transcription. (a) qPCR analysis of Cyp7b1 male-biased DHS [Fig. 3(e)] for intact and hypophysectomized male and female mouse livers, with a time course of GH treatment as in Fig. 2. (b and c) RT-qPCR analysis of Cyp7b1 hnRNA and mRNA reveals that male-specific transcription is abolished by hypophysectomy, but fails to be induced by a GH pulse. Transcription rates and mRNA levels are not significantly different between STAT5-high and STAT5-low livers. Data shown in the left set of graphs (hypophysectomy series) are mean ± SEM values for n = 5 to 9 livers per group, except for DHS analysis of the intact male group, where n = 18. The right set of graphs (STAT5-high, STAT5-low) are based on n = 9 to 12 livers per group. Relative DHS activity and expression level of the intact male (left) and the STAT5-high groups (right) are set to 1. Significance values by ANOVA or two-tailed t test are indicated as described in the Fig. 2 legend.