eLife assessment
This important study offers new and convincing support for the idea that about a third of mouse liver DNAse hypersensitivity sites (DHS) showing male-biased chromatin opening are sex-biased because of the male-specific cyclic action of growth hormone pulses to alter chromatin accessibility, as compared to the relative ineffectiveness of the more static pattern of growth hormone secretion in females. Supporting evidence is found in the impact of hypophysectomy and growth hormone treatment on chromatin accessibility, and the binding of specific transcription factors and epigenetic marks at STAT5-sensitive sites. This work uncovers mechanisms underlying sex differences in liver function and will be of broad interest to endocrinologists and hepatologists.