animal experiment nonhuman 89 Animals 72 controlled study 72 animal 69 Article 66 mouse 50 animal model 48 male 48 animal tissue 45 animal cell 44 human 38 metabolism 38 female 35 Mice 34 unclassified drug 28 Humans 27 in vivo study 25 rat 25 article 23 Male 19 genetics 19 human cell 19 priority journal 19 protein expression 19 Rats 18 drug effect 18 in vitro study 18 Female 17 physiology 17