Comparative distribution of somatostatin and thrittene bioactive peptides in the central nervous system of rat measured by radioimmunoassay

In the present paper the development and application of a novel somatostatin radioimmunoassay are described. 125I-labeling of Tyr(0)-somatostatin-14 (tyrosin(0)-somatostatin-14) was performed by the iodogen-method and the mono-iodinated peptide was separated by reversed-phase HPLC. As a practical application of the novel RIA, the present work measured the somatostatin concentration parallel with the determination of thrittene content in different rat brain areas. The highest somatostatin concentrations were detected in the cerebellum. The thrittene immunoreactivity in the same brain parts showed a similar tendency. In the present study concluded that thrittene is not created via a specific biosynthetical route, but from the pre-prosomatostatin.