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Horm Metab Res 1977; 9(3): 195-199
DOI: 10.1055/s-0028-1093535
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© Georg Thieme Verlag KG Stuttgart · New York

Disparity Between Insulin and Proinsulin on Stimulation of Hepatic Tyrosine Transaminase

M. B. Davidson1 , L. E. Gerschenson2
  • 1Department of Medicine, UCLA School of Medicine, Los Angeles, California, USA
  • 2Laboratory of Nuclear Medicine and Radiation Biology, Department of Pathology, UCLA School of Medicine, Los Angeles, California, USA
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Publication History

Publication Date:
23 December 2008 (online)

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Abstract

The ability of insulin and proinsulin to stimulate tyroxine transaminase in dexamethasone-treated cultured rat liver cells was compared. Insulin increased this enzyme whereas proinsulin was seemingly without effect. Since proinsulin was not degraded by these cells, failure of stimulation of hepatic tyrosine transaminase could not be due to rapid destruction of the prohormone. This is the first demonstration of an action of insulin that cannot be duplicated by proinsulin.

Key words

Proinsulin - Insulin - Tyrosine Transaminase - Liver Cell Culture

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