Animals animal cell article nonhuman 1,274 controlled study 1,042 priority journal 1,000 Mice 632 mouse 578 animal experiment 460 unclassified drug 412 protein expression 404 Female 364 animal tissue 348 female 348 Rats 342 Humans 324 rat 304 animal model 296 Male 280 male 266 human 262 Animalia 258 animal 250 signal transduction 210 metabolism 204 human cell 192 cell proliferation 190 messenger RNA 168 Cells, Cultured 166 Cell Line 164