controlled study male nonhuman protein expression animal experiment 201 Animals 197 priority journal 195 Male 183 article 183 animal tissue 148 animal cell 143 mouse 130 animal model 111 Mice 102 female 95 animal 79 rat 76 Article 74 human 73 metabolism 71 messenger RNA 68 unclassified drug 66 Female 61 Humans 59 human cell 57 Rats 54 in vivo study 52 immunohistochemistry 50 cell proliferation 49 protein function 46