Distribution and Degradation Studies with Insulin-I131†
1954; American Society for Clinical Investigation; Volume: 33; Issue: 9 Linguagem: Inglês
10.1172/jci103000
ISSN1558-8238
AutoresNeil J. Elgee, Robert H. Williams, Norman D. Lee,
Tópico(s)Hyperglycemia and glycemic control in critically ill and hospitalized patients
ResumoDiabetes mellitus is of obscure etiology, often presenting profound metabolic derangement with a sparsity of morphopathologic change.Insulin reverses many of the metabolic changes, yet its mechanism of action is poorly understood; fur- thermore, in most patients with diabetes mellitus, the fundamental causes of the insulin insufficiency are not known.An important approach to this challenging problem is the study -of insulin metab- olism.Such a study has been hampered by un- satisfactory assay techniques, and, as a-result, very little is known even of the fate of insulin.The use of labeled hormone greatly facilitates such a study, and, in this report, the validity of such an ap- proach is considered, and distribution and degradation studies using I'8l-labeled insulin are described. METHODS AND MATERIALSInsulin-I' Crystalline zinc insulin 8 was labeled with I', either by the method of Ferrebee, Johnson, Mithoefer, and Gar- della (1), or by a method of the Abbott laboratories.Specific activity ranged from 4 to 1008 i'c per mg.The radioactivity of the insulin-I' stayed with the protein fraction in trichloracetic acid precipitation, in dialysis, and in chromatography.4It had the same mobility as un- labeled insulin in paper electrophoresis (2).The potencies of three different lots of insulin-I', two prepared by the Ferrebee technique, and one by the Abbott method, were tested in the acceleration of the glucose uptake of rat diaphragm in vitro.Each determination
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