Pancreatic islets were prepared from 22-day-old rat fetuses. After 5 days of culture in dishes allowing cell attachment, neoformed islets were kept free floating in RPMI-1640 medium (16.5 mM glucose, 1% fetal calf serum). The islets were then pulsed with [3H]leucine and [35S]methionine for 24 h. The conditioned medium was acidified with acetic acid (final pH 2.7), desalted, concentrated, and gel filtered on Bio-Gel P100 in acid conditions. The radioactive material that comigrated with immunoreactive insulinlike growth factor I (IGF-I) produced by the islets was pooled, concentrated, and further characterized by reverse-phase high-performance liquid chromatography on a C18Bondapak column with a linear gradient of acetonitrile (20–80%). The radioactive material that eluted as pure IGF-I (40% acetonitrile) was further studied by chromatofocusing on a Pharmacia PBE 94 column. A sharp radioactive peak containing [3H]leucine and [35S]methionine was eluted at pH 8.55. This material was immunoprecipitated with an antiserum to IGF-I. This study demonstrated that fetal islet cells synthesize molecules that are, by several criteria, equivalent to native IGF-I.
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Original Articles| June 01 1989
Characterization of Insulinlike Growth Factor I Produced by Fetal Rat Pancreatic Islets
Address correspondence and reprint requests to Paul Czernichow, MD, Hôpital Robert Debzé 48 Boulevard Serurier Paris 19, France.
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Raphaël Scharfmann, Maité Corvol, Paul Czernichow; Characterization of Insulinlike Growth Factor I Produced by Fetal Rat Pancreatic Islets. Diabetes 1 June 1989; 38 (6): 686–690. https://doi.org/10.2337/diab.38.6.686
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