animal experiment controlled study nonhuman 359 unclassified drug Animals 275 article 235 priority journal 235 mouse 204 animal model 187 animal tissue 181 animal cell 168 Mice 149 animal 142 female 139 male 138 protein expression 136 metabolism 121 Female 120 Article 118 Male 118 human 98 rat 92 Humans 90 Rats 78 messenger RNA 68 in vivo study 65 in vitro study 63 enzyme activity 62 physiology 60 human cell 58