Localization of exogenous 14C-oxalate in rats determined by whole-body- and microautoradiography.

A single dose of 14C-oxalate was given to Wistar rats using a throat probe. The animals were sacrificed and the oxalate distribution was determined using whole-body-autoradiography. The results showed that a large portion of the absorbed oxalate had reached the bladder 30 min after administration. It is possible that this rapid renal excretion could lead to a short-term oxalate peak in the urine. The oxalate also showed a great affinity for bone. This suggests that there is a deep compartment for oxalate in bone. At the light microscopic level, the localization of 14C-oxalate in bone and in the gastric wall was demonstrated using microautoradiography. This appears to show that there is gastric excretion of absorbed oxalate. Further pharmacokinetic investigations are necessary to confirm this conclusion.