Comparison of the Physico-Chemical and Physiological Behavior of Natural Inulin with Its Radioactive Derivatives. ∗

Abstract

Summary

In several in vitro systems it has been found that the C¹⁴ (inulin-C¹⁴OOH) and H³ (inulin-OCH³ ₃) labelled derivatives behave differently from ordinary inulin. Several lots passed faster than inulin through cellophane tubing in dialysis or centrifugal-pressure ultrafiltration. Size differences were also demonstrated by gel filtration through Sephadex G-50 column. Migration of inulin-C¹⁴OOH from inulin occurred in paper electrophoresis because of its anionic nature. Following a single i.v. injection to a dog, urine C¹⁴ specific activity was not higher than administered dose but fell with time, showing that the glomerular capillaries did not restrict filtration of inulin as compared with the smaller inulin-C¹⁴OOH. It is suggested that a more rapid rate of extrarenal removal of the radioactive inulin-C¹⁴OOH occurred.