animal tissue controlled study nonhuman 183 priority journal unclassified drug Animals 151 article 141 animal experiment 118 animal cell 87 mouse 86 male 79 Mice 68 female 66 rat 63 Male 59 animal model 58 animal 57 Female 52 metabolism 52 Rats 51 protein expression 51 Article 46 messenger RNA 38 enzyme activity 37 signal transduction 30 Rats, Sprague-Dawley 29 human 28 Humans 26 RNA, Messenger 26 Gene Expression Regulation 24