article controlled study priority journal unclassified drug nonhuman 605 Animals 397 animal cell 286 Humans 201 human 193 mouse 179 protein expression 177 Mice 176 animal experiment 169 animal tissue 141 human cell 138 male 121 female 120 enzyme activity 110 protein function 110 Female 108 Male 103 rat 103 Rats 99 animal model 86 metabolism 78 messenger RNA 71 nucleotide sequence 65 signal transduction 65 gene expression 63 in vitro study 63