Renal uptake and retention of radiolabeled somatostatin, bombesin, neurotensin, minigastrin and CCK analogues: species and gender differences

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• 作者：Marleen Melis ; Eric P. Krenning ; Bert F. Bernard ; Monique de Visser ; Edgar Rolleman ; Marion de Jong
• 关键词：Radiolabeled peptides ; Renal retention ; Rat ; Mouse ; Gender
• 刊名：Nuclear Medicine and Biology
• 出版年：2007
• 出版时间：August 2007
• 年：2007
• 卷：34
• 期：6
• 页码：633-641
• 全文大小：1183 K

文摘

During therapy with radiolabeled peptides, the kidney is most often the critical organ. Newly developed peptides are evaluated preclinically in different animal models before their application in humans. In this study, the renal retention of several radiolabeled peptides was compared in male and female rats and mice.

Methods

After intravenous injection of radiolabeled peptides [somatostatin, cholecystokinin (CCK), minigastrin, bombesin and neurotensin analogues], renal uptake was determined in both male and female Lewis rats and C57Bl mice. In addition, ex vivo autoradiography of renal sections was performed to localize accumulated radioactivity.

Results

An equal distribution pattern of renal radioactivity was found for all peptides: high accumulation in the cortex, lower accumulation in the outer medulla and no radioactivity in the inner medulla of the kidneys.

In both male rats and mice, an increasing renal uptake was found: [¹¹¹In-DTPA]CCK8<[¹¹¹In-DTPA-Pro¹,Tyr⁴]bombesin≈[¹¹¹In-DTPA]neurotensin<[¹¹¹In-DTPA]octreotide[¹¹¹In-DTPA]MG0. Renal uptake of [¹¹¹In-DTPA]octreotide in rats showed no gender difference, and renal radioactivity was about constant over time. In mice, however, renal uptake in females was significantly higher than that in males and decreased rapidly over time in both genders. Moreover, renal radioactivity in female mice injected with [¹¹¹In-DTPA]octreotide showed a different localization pattern.

Conclusions

Regarding the renal uptake of different radiolabeled peptides, both species showed the same ranking order. Similar to findings in patients, rats showed comparable and constant renal retention of radioactivity in both genders, in contrast to mice. Therefore, rats appear to be the more favorable species for the study of the renal retention of radioactivity.