Abstract
Summary
Tritiated synthetic gastrin I: 1-17 and a C-terminal peptide analogue (BOC-Gly-Trp-Met-Asp-PheNH2) with a specific radioactivity of 45 and 7 Ci/mmole respectively, was found to disappear very rapidly from the blood when given iv to anesthetized rats. The calculated half-life for gastrin and the peptide analogue was 1.8 and 3.0 min respectively. The tissues which showed the greatest affinity for radioactivity with gastrin was the kidney, gastric fundus, liver and pancreas in the order of concentration. With pentagastrin, the pancreas, liver and proximal duodenum concentrated radioactivity to the highest degree.
The results also indicate that, once injected into the rat, the labelled products which remain in the blood undergo modification. Although the results presented do not give any indication how these modifications take place, it is possible that the organs which sequester the products modify them and then re-released them into the blood stream. Whether or not these modified forms are active biologically is open to conjecture.
This research was supported in part by a grant from the Smith, Kline and French Laboratories, Philadelphia, Pennsylvania.
Supported in part by a grant from the D.G.R.S.T. No. 73-7-1633.
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