The University of Georgia College of Veterinary Medicine

eorgia Veterinary Scholars Program

GVSP Summer 2007 Scholars

Georgia Veterinary Scholar	Faculty Mentor

Robert Steen University of Georgia Class of 2010	Dr. Cynthia Ward

Flavonioids Stimulate Mitogenesis and Thyroglobulin Production in Cultured Feline Hyperthyroid Cells

NC Rupp, RE Steen*, and CR Ward, Department of Small Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA

Feline hyperthyroidism is a common disease in domestic cats. Based on previous studies it has been shown that age and exposure to canned foods are the most important risk factors for the disease. Canned cat foods have been shown to contain a significant concentration of flavonoid plant proteins. Because cats are obligate carnivores, it is hypothesized that flavonoids are risk factors for hyperthyroidism. This study examines the potential of flavonoids to stimulate mitogenesis and thyroglobulin production, two measures of thyroid cell functionality, in cultured feline hyperthyroid cells. Two immortalized feline hyperthyroid cell lines, PetCat 1 and PetCat 2, were established in culture, replated, starved for 6 days in a minimal medium, and then stimulated with thyroid stimulating hormone, the natural ligand, and various concentrations of the flavonoids, myrecetin, fiscetin, or biochanin A. Mitogenesis and thyroglobulin production were determined by bromodeoxyuridine (BrdU) uptake and thyroglobulin synthesis. Positive cells were determined by epiflourescence microscopy using fluorochrome-labeled BrdU and thyroglobulin antibodies. A flow cytometric protocol to determine positively labeled cells is being developed to increase objectivity and ease of data collection. The first part of the summer has been spent becoming familiar with general cell culture and antibody-labeling techniques. Both PetCat 1 and PetCat 2 cell lines have been successfully grown, starved, and stimulated with the proposed ligands. Several antibody techniques have been tried in order to determine the optimal protocol for flow cytometry. Once optimized, flow cytometry will be used to determine the effect three flavonoids (myrecetin, fiscetin, and biochanin A) have on mitogenesis and thyroglobulin production. The effect of the flavonoids will be compared to that of the natural thyroid stimulating hormone ligand. We believe that myrecetin, fiscetin, and biochanin A will stimulate mitogenesis and thyroglobulin production above baseline and to a greater level than that seen with thyroid stimulating hormone.