human metabolism Humans 743 controlled study 399 animal 397 Animals 379 priority journal 349 nonhuman 331 article 310 genetics 307 human cell 281 Article 274 unclassified drug 239 chemistry 229 female 221 physiology 204 protein expression 196 Female 194 signal transduction 186 mouse 169 animal cell 148 Mice 145 pathology 139 drug effects 134 male 121 in vitro study 118 protein function 115 Signal Transduction 113 cell line 111 drug effect 111