Rats animal rat 175 article 133 metabolism 130 Animals 105 nonhuman 83 Animal 74 animal experiment 59 controlled study 56 drug effect 56 Male 55 male 55 female 51 physiology 51 priority journal 50 Female 48 animal cell 43 enzymology 39 in vitro study 36 Support, Non-U.S. Gov't 34 unclassified drug 31 Article 30 biosynthesis 30 human 30 Rats, Sprague-Dawley 28 Sprague Dawley rat 28 chemistry 25 Humans 24 Rats, Wistar 24