Animals Male article nonhuman priority journal male 485 controlled study 476 animal experiment 413 animal tissue 311 Female 230 Mice 226 animal cell 216 mouse 214 female 194 Rats 179 animal model 173 rat 168 protein expression 128 unclassified drug 101 Rats, Sprague-Dawley 95 Animalia 93 Humans 77 Time Factors 76 messenger RNA 71 animal 67 drug effect 66 enzyme activity 66 Immunohistochemistry 65 RNA, Messenger 64 Memory 59