animal tissue controlled study nonhuman protein expression Animals 278 animal experiment 264 priority journal 254 article 248 mouse 179 animal cell 169 animal model 167 female 162 Mice 149 male 148 Female 133 rat 113 Male 111 Rats 93 animal 88 messenger RNA 84 unclassified drug 84 Article 82 metabolism 80 immunohistochemistry 79 human 70 enzyme activity 65 in vivo study 65 Humans 64 Western blotting 64 Rats, Sprague-Dawley 63