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INCORPORATION OF TRITIATED LEUCINE INTO INSULIN ANALOGUES IN VITRO

Human pancreas was taken from three patients, one was a patient with esophageal cancer, two with gastric cancer as surgical specimen. Excised pancreas was incubated in Krebs Henseleit bicarbonate buffer with 0.6 or 3.0 mg/ml glucose and L-[4,5-3H(N)]-leucine. The incubation medium and incubated pancreas were gel chromatographed on the Bio-Gel column after extraction with acid-ethanol. The radioactivity of each fraction was determined by a liquid scintillation counter after addition of Bray's scintillator liquid. Each of fraction was assayed for immunoreactive insulin, C-peptide immunoreactivity and glucagon immunoreactivity. Two peaks of insulin were detected in the incubation medium and the incubated pancreas at the position of 6000 molecular weight region. Each peak of insulin was not corresponded to that of 3H-leucine radioactivity in all experiments. Also the peak of tritiated leucine was not corresponded to that of C-peptide and glucagon. These findings suggest that there are two kinds of insulin both in the incubation medium and in the incubated pancreas, but the estimation of incorporated radioactivity of 3H-leucine has to be verified for evaluation of insulin biosynthesis itself in this way of experiment.

著者名
Kakita K, et al
5
3.4
177-183
DOI
10.11482/KMJ-E5(3.4)177

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