protein expression nonhuman 1,059 controlled study 1,003 priority journal 973 article 944 Animals 835 human 613 Humans 541 animal cell 523 unclassified drug 472 animal experiment 456 mouse 441 Mice 416 female 382 Female 362 animal tissue 362 metabolism 353 human cell 348 protein function 324 male 310 signal transduction 288 Article 276 animal 275 animal model 268 Male 258 messenger RNA 228 cell proliferation 227 enzyme activity 218 rat 206 apoptosis 198