Avian gonadotropin-releasing hormones I and II in brain and other tissues in turkey hens.

1. Radioimmunoassays were developed for measuring avian gonadotropin-releasing hormones I and II (cGnRH I and II) in tissue extracts during the reproductive cycle. 2. Hypothalamic concentrations of cGnRH I and II were qualitatively similar being lowest in non-photostimulated hens, greater in laying hens and greatest in incubating hens. 3. cGnRH II concentrations were similar in paraolfactory lobe and hypothalamic fragments while lesser amounts were found in cerebrum, cerebellum, duodenum, shell gland, and pineal. 4. These results suggest that cGnRH II has unknown functions in turkeys quite distinct from traditional functions associated with GnRHs.