Radioimmunoassay Animals 40 Female 38 nonhuman 38 article 36 female 30 Male 28 animal experiment 28 priority journal 28 animal tissue 24 controlled study 22 male 22 radioimmunoassay 22 animal cell 20 Mice 18 Rats 18 rat 18 metabolism 16 mouse 16 protein expression 16 Estradiol 14 Progesterone 14 animal 14 estradiol 14 immunohistochemistry 14 progesterone 14 Gonadotropin-Releasing Hormone 12 Immunohistochemistry 12 Luteinizing Hormone 12 luteinizing hormone 12