期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1971
卷号：68
期号：8
页码：1833-1837
DOI：10.1073/pnas.68.8.1833
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：With [125I]insulin at 7 x 10-10 M, 25% of the radioactivity was bound to plasma membranes purified from rat liver. 20% of the [125I]insulin binding was inhibited by unlabeled insulin at 10-9 M (6 ng/ml), equivalent to insulin concentrations in hepatic portal blood; inhibition of [125I]insulin binding was 80% at 10-7 M and 90% at 10-5 M. Eight insulins and derivatives with biological potencies that differed over a 100-fold range inhibited the binding of [125I]insulin to liver membranes in direct proportion to their ability to stimulate glucose oxidation in isolated fat cells. Inactive insulin chains, as well as glucagon, ACTH, and human growth harmone were without effect. The binding of [125I]insulin increased 55-fold as plasma membrane was purified from crude homogenate. Binding was time- and temperature-dependent, and addition of excess insulin produced rapid dissociation of [125I]insulin. This study demonstrates directly the binding of insulin to its biologically important receptors.
