Male controlled study male 60 metabolism 56 Article 52 human 47 Humans 45 adult 40 female 39 Female 38 genetics 33 nonhuman 27 pathology 26 unclassified drug 26 Animals 25 middle aged 25 Middle Aged 24 animal 24 gene expression regulation 23 protein expression 23 upregulation 22 animal experiment 21 gene expression 21 Adult 20 down regulation 20 human cell 20 animal model 19 major clinical study 19 human tissue 18 animal tissue 17