Abstract
The study and comparison of the metabolism of selected somatostatin analogues, namely DOTA-Tyr(3)-octreotate (DOTA-TATE) labelled with In-111, Y-90 and Lu-177 and two radioiodinated peptides glucose-Tyr(3)octreotate and DOTA-TATE was carried out in rats. Whereas the peptides labelled with radiometals were eliminated into urine mostly in the parent form, a significant portion of metabolites of iodinated compounds (especially in the longer time intervals after dosing) in rat urine were found.
High radioactivity uptake in organs with high density of somatostatin receptors (the pancreas and adrenals) and also in the kidney was determined. Whereas high radioactivity accumulation in the above-mentioned organs continued for a long time for the peptides labelled with radiometals, this uptake significantly decreased with time for iodinated derivatives.