article rat nonhuman 437 Rats 431 controlled study 339 priority journal 328 Animals 310 animal experiment 282 animal cell 206 animal tissue 204 male 200 female 196 Female 183 Male 183 Rats, Sprague-Dawley 157 animal 136 Animal 128 Animalia 111 unclassified drug 111 metabolism 105 animal model 98 Rats, Wistar 96 Support, Non-U.S. Gov't 82 protein expression 82 enzyme activity 78 drug effect 73 Liver 56 in vitro study 52 Rats, Inbred Strains 50 Humans 45