animal cell endocrine system 100 nonhuman 100 rat 84 Rats 72 radioisotope 68 Animal 64 priority journal 56 Rats, Inbred Strains 52 Support, Non-U.S. Gov't 52 Female 48 pharmacokinetics 38 drug receptor binding 36 Male 34 drug efficacy 34 animal experiment 28 Animals 26 central nervous system 26 female genital system 26 article 24 In Vitro 22 drug interaction 22 unclassified drug 22 Pineal Gland 18 Progesterone 18 adrenal gland 18 pineal body 18 Estradiol 16 dose response 16 estradiol 16