Our established gonadotroph cell lines will be used to better define the regulatory mechanisms for the secretion of gonadotrophins (FSH and LH). We plan to examine direct effects of a number of agents such as neurohumoral substances and steroids which are known to influence gonadotrophin-secretion using our established gonadotroph-rich cell line, or cell lines derived from neonatal or immature rat pituitary glands. Morphological studies of gonadotroph cell lines will be performed by immunocytochemistry in order to define the localization of FSH and LH in the cells. We will also continue our electron microscopic examinations on gonadotroph cell lines.