animal human cell 136 metabolism human 134 Animals 132 Humans 118 controlled study 116 nonhuman 104 mouse 88 Mice 80 animal cell 80 unclassified drug 70 article 66 Article 60 priority journal 60 animal experiment 56 genetics 52 protein expression 52 chemistry 48 animal model 46 in vivo study 42 cell line 38 pathology 38 signal transduction 36 Cell Line 34 female 34 physiology 34 cell proliferation 32 in vitro study 32 tumor cell line 32