animal tissue article controlled study nonhuman 189 unclassified drug Animals 159 priority journal 141 animal experiment 121 animal cell 82 male 82 mouse 78 rat 72 Male 70 Mice 68 Rats 64 female 64 animal model 58 Female 56 protein expression 50 animal 41 metabolism 40 Rats, Sprague-Dawley 38 messenger RNA 38 enzyme activity 37 protein function 30 Humans 27 RNA, Messenger 27 Animalia 26 human 25 Signal Transduction 24