Robert W. Freel, Ph.D.
|UF Department of Pathology, Immunology and Laboratory Medicine
College of Medicine
P.O. Box 100275
Gainesville, FL 32610
Dr. Freel’s overall research interests include the mechanisms and regulation of solute transport across epithelial membranes in health and disease. His team’s efforts are directed at understanding the cellular mechanisms mediating the secretion of oxalate and other divalent anions by renal and intestinal epithelia. The oxalate anion is of considerable importance because it forms insoluble complexes with calcium in the lumen of the renal tubule leading, in some conditions, to the formation of renal stones.
Their recent studies suggest that the intestinal secretion of oxalate occurs via cAMP-stimulated transport pathways that are similar (if not identical) to those mediating monovalent anion secretion; additionally, these pathways are up-regulated when renal function is impaired, providing an extrarenal pathway for the excretion of the oxalate anion.
Dr. Freel’s team now employs a variety of approaches to establish the nature of apical membrane oxalate conductance (patch clamp, membrane vesicles, using chambers); the impact of variable intracellular oxalate on cell calcium signaling in oxalate transporting epithelia (spectrofluorometry); and the regulatory pathways involved in enhanced enteric oxalate secretion (real time-PCR and other molecular biological techniques).
The team also maintains an active interest in the regulation of potassium ion transport by the mammalian large intestine. Their studies in this area have provided two novel regulatory pathways for potassium ion secretion in the large intestine: an angiotensin II receptor mediated up-regulation of potassium ion secretion and muscarinic down-regulation of potassium ion secretion.