article 54 rat strain 54 Rats 52 rat 52 animal 42 Rats, Inbred Strains 40 Animal 36 metabolism 32 nonhuman 30 Male 28 Support, Non-U.S. Gov't 28 animal experiment 28 male 28 drug effect 20 priority journal 20 Female 18 female 18 Animals 16 controlled study 16 in vitro study 12 radioisotope 12 In Vitro 10 Liver 10 animal cell 10 liver 10 Dinoprostone 8 Kinetics 8 Norepinephrine 8 Prostaglandins E 8 Uterus 8