Euishin Edmund Kim MD, Abstract Co-Author: Nothing to Disclose

Ho-Chun Song MD, Abstract Co-Author: Nothing to Disclose

David J. Yang PhD, Presenter: Nothing to Disclose

This study was aimed to assess pancreas beta cell activity using 99mTc-DTPA-glipizide (DTPA-GLP), a sulfonylurea receptor agent. The effect of DTPA-GLP on blood glucose level in rats was also evaluated.

DTPA dianhydride was conjugated with GLP in dimethylsulfoxide, yielded 60%. Biodistribution and planar images were obtained at 30-120 min after injection of 99mTc-DTPA-GLP (1 mg/rat) in normal healthy female Fischer 344 rats (150-175 g) via tail vein. The control group was given 99mTc-DTPA. The doses for biodistribution and imaging studies were 25 and 300μCi per rat respectively. To demonstrate pancreas beta cell uptake of 99mTc-DTPA-Glipizide (GLP) is via a receptor-mediated process, a group of rats were pretreated with streptozotocin (a beta cell toxin, 55 mg/kg, iv) and the images were acquired at immediately-65 min on day 5 post-treatment. The effect on glucose levels after a single administration (ip) of DTPA-GLP was compared to the parent agent for up to 6 hours.

The structure of DTPA-GLP was confirmed by NMR, mass spectrometry and HPLC. 99mTc-DTPA-GLP showed increased pancreas-to-muscle ratios whereas 99mTc-DTPA showed decreased ratios at various time-points. Pancreas could be visualized with 99mTc-DTPA-GLP in normal rat, however, 99mTc-DTPA has poor uptake suggesting the specificity of 99mTc-DTPA-GLP. Pancreas beat cell uptake could be blocked by pre-treatment with streptozotocin. The finding indicated that pancreas beta cell uptake of 99mTc-DTPA-GLP is via a receptor mediated process. DTPA-GLP showed an equal or better response in lowering glucose levels compared to the existing GLP drug.

It is feasible to use 99mTc-DTPA-GLP to assess pancreas beta cell receptor recognition. 99mTc-DTPA-GLP may be helpful in evaluating patients with diabetes, pancreatitis and pancreatic tumors.

99mTc-DTPA-GLP is a potential islet imaging agent.

Kim, E, Song, H, Yang, D, Development of 99mTc-DTPA-GLP as a Novel Islet Imaging Agent.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6022090.html