The research proposed in this application addresses basic biological questions concerning the normal functioning of the pancreatic islet in the anglerfish. This animal is ideally suited for the proposed studies since it affords the highest yield of pancreatic endocrine cells of any species currently known. The proposed studies will add significant novel insight into the anatomical distribution and also the nutrient and neurotransmitter regulation of a key enzyme (peptidyl-glycine alpha-amidating mono-oxygenase- PAM) which is involved in the post- translational processing of islet endocrine hormones. Furthermore the proposed investigations will significantly increase our understanding of the regulation of islet hormone secretion by two major neurotransmitters, norepinephrine and neuropeptide Y, which are distributed throughout the animal kingdom. The results of these studies will provide new insight into basic mechanisms of islet cell function and regulation by the nervous system in anglerfish and there is also a very high probability that these findings will be applicable to several other species.