superior cervical ganglionectomy animal experiment 20 rat 20 Rats 16 endocrine system 16 Animal 14 Male 12 autonomic nervous system 12 pineal body 12 Ganglia, Sympathetic 10 Pineal Gland 10 Rats, Inbred Strains 10 nonhuman 10 radioisotope 10 Female 8 Superior cervical ganglion 8 central nervous system 8 pinealectomy 8 Castration 6 Kinetics 6 Norepinephrine 6 Support, Non-U.S. Gov't 6 castration 6 Cyclic AMP 4 Estradiol 4 Gonadotropins, Pituitary 4 Hypothalamus, Middle 4 Isoproterenol 4 Luteinizing Hormone 4 Pineal gland 4