Animals metabolism unclassified drug animal 291 nonhuman 266 controlled study 225 priority journal 160 Article 146 human 138 animal cell 133 Humans 131 animal experiment 123 article 123 mouse 121 genetics 113 Mice 105 animal tissue 100 protein expression 95 chemistry 94 physiology 92 female 79 messenger RNA 74 drug effects 68 Female 67 protein function 66 human cell 65 male 63 rat 61 animal model 60 signal transduction 60