The hormone calcitonin is best known for its ability to reduce bone demineralization in mammals and, as a result of this action, it is regularly administered to patients experiencing osteoporosis, Paget's disease, or similar skeletal maladies. However, despite its therapeutic value for skeletal diseases, a growing body of evidence has suggested that the true physiological function of calcitonin may be to regulate certain aspects of vertebrate reproduction. Recently, the PI has demonstrated similar evidence of a role for calcitonin in regulating events during pregnancy in live-bearing sharks and rays, the oldest living vertebrate group known to possess the ultimobranchial gland, the site of calcitonin production. In this project, the PI will receive new training in molecular biology, which will clarify the roles of calcitonin in elasmobranch reproduction by examining patterns of calcitonin and calcitonin receptor gene expression in gravid female rays and their offspring. Following completion of an intensive, 3-week training course in molecular biology, protein chemistry, and bioinformatics at the University of Florida's Interdisciplinary Center for Biotechnology Research, the PI and two student interns will utilize RT-PCR, Northern blot analysis, and in situ hybridization to determine: 1) if increases in ultimobranchial gland activity previously shown to occur during pregnancy in this species reflect changes in calcitonin production; 2) if tissues other than the ultimobranchial gland synthesize calcitonin; and 3) where calcitonin receptors are expressed and if these expression patterns change during reproduction. By obtaining this information, this project will significantly advance knowledge regarding both reproductive physiology and endocrine function in the cartilaginous fishes and the role of calcitonin in vertebrates. Furthermore, both the training and laboratory instrumentation supported by this grant will enhance the infrastructure for research and student training opportunities in the PI's laboratory. The PI is a Native Pacific Islander researcher who makes significant contributions to both his field of study and undergraduate science education, especially that for underserved minority groups.
