animal model rat nonhuman 258 animal experiment 235 controlled study 216 article 202 Rats 199 priority journal 171 Animals 167 animal tissue 130 female 127 Female 118 animal cell 99 male 97 Male 83 Rats, Wistar 75 Rats, Sprague-Dawley 71 protein expression 63 unclassified drug 50 enzyme activity 49 Animalia 47 Hexachlorobenzene 40 hexachlorobenzene 40 Liver 39 Animal 38 animal 37 progesterone 37 Support, Non-U.S. Gov't 36 Article 34 mouse 32