drug effects metabolism nonhuman controlled study 100 Animals 90 animal 90 Article 89 animal experiment 59 priority journal 56 mouse 49 animal cell 45 male 45 animal tissue 44 female 39 unclassified drug 39 Mice 38 Male 33 genetics 33 protein expression 32 human 31 Humans 29 physiology 29 Female 28 animal model 28 in vitro study 22 adult 21 toxicity 20 chemistry 19 signal transduction 19 enzyme activity 18