A new scintigraphic technique for cholecystokinin gallbladder dose-response study: validation in rabbits

Area of Science:

• Gastroenterology
• Pharmacology
• Nuclear Medicine

Background:

• Establishing accurate dose-response curves for gastrointestinal peptides is crucial for drug development.
• Cholecystokinin (CCK)-like agents, such as ceruletide, play a significant role in gallbladder motility.
• Traditional methods for dose-response assessment often require multiple patient visits.

Purpose of the Study:

• To determine if a dose-response curve for ceruletide can be reliably established using sequential dosing on a single day.
• To compare the accuracy of sequential dosing with traditional single-dose administration on separate days.
• To evaluate the efficiency and simplicity of the sequential dosing method.

Main Methods:

• Gallbladder ejection fraction (EF) was measured using Tc-99m-IDA counts to assess gallbladder bile volume.
• Ceruletide was administered in graded doses (1, 2.5, 5, 10 ng/kg) sequentially on the same day.
• Results were compared to EF values obtained from separate single-dose administrations on different days.

Main Results:

• Sequential dosing yielded mean EF values of 10±8%, 22±12%, 53±13%, and 85±3% for 1, 2.5, 5, and 10 ng/kg, respectively.
• Single-dose administration on separate days produced similar EF values (2.5 ng/kg: 29.7%, 5 ng/kg: 57.14%, 10 ng/kg: 93.3%).
• The similarity in results between the two methods was statistically significant (P < 0.05).

Conclusions:

• Sequential dosing of ceruletide on the same day is an accurate method for establishing dose-response curves.
• This simplified approach is as reliable as administering single doses on separate days.
• The sequential method offers a more convenient and efficient alternative for future studies involving CCK-like agents.