Insulin's effect on protein kinase C and diacylglycerol induced by diabetes and glucose in vascular tissues

Toyoshi Inoguchi, P. Xia, M. Kunisaki, S. Higashi, E. P. Feener, G. L. King

    Research output: Contribution to journalArticle

    Abstract

    We have reported that membranous protein kinase C (PKC) activities and total diacylglycerol (DAG) levels are increased in the heart and aorta of diabetic rats, which cannot be easily reversed by euglycemic control. However, insulin treatment, which achieved euglycemia, can prevent the increase in PKC activities and DAG levels. Chronic exposure to elevated glucose levels (5.5 vs. 22 mM) increased DAG levels in cultured bovine and rat aortic endothelial cells and smooth muscle cells by 31, 140, and 143%, respectively, only after 3 days of incubation. Glyceraldehyde, which can stimulate the de novo synthesis of DAG, significantly increased DAG levels by 7.1 ± 0.6-fold after only 16 h of incubation. Elevated glucose levels did not affect labeled DAG when all of the vascular cells were incubated with [3H]arachidonate, [3H]glycerol, or [3H]phosphatidylcholine, whereas [3H]palmitate- and [3H]oleic acid-labeled DAG levels were significantly increased, indicating that the glucose-stimulated increase in DAG is derived partially from the de novo synthesis pathway. Immunoblotting studies showed increases only in PKC isoform βII but not α in aortic smooth muscle cells. The phosphorylation level of MARCKS protein, an intracellular substrate of PKC, was also increased, consistent with the PKC activity increase. These findings showed that diabetic and hyperglycemia-induced increases in PKC activity and DAG levels in the heart and aorta are preventable by insulin treatment.

    Original languageEnglish
    JournalAmerican Journal of Physiology - Endocrinology and Metabolism
    Volume267
    Issue number3 30-3
    Publication statusPublished - Jan 1 1994

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    Diglycerides
    Protein Kinase C
    Blood Vessels
    Glucose
    Smooth Muscle Myocytes
    Aorta
    Insulin
    Glyceraldehyde
    Palmitates
    Oleic Acid
    Phosphatidylcholines
    Immunoblotting
    Hyperglycemia
    Glycerol
    Protein Isoforms
    Endothelial Cells
    Phosphorylation

    All Science Journal Classification (ASJC) codes

    • Endocrinology, Diabetes and Metabolism
    • Physiology
    • Physiology (medical)

    Cite this

    Insulin's effect on protein kinase C and diacylglycerol induced by diabetes and glucose in vascular tissues. / Inoguchi, Toyoshi; Xia, P.; Kunisaki, M.; Higashi, S.; Feener, E. P.; King, G. L.

    In: American Journal of Physiology - Endocrinology and Metabolism, Vol. 267, No. 3 30-3, 01.01.1994.

    Research output: Contribution to journalArticle

    Inoguchi, Toyoshi ; Xia, P. ; Kunisaki, M. ; Higashi, S. ; Feener, E. P. ; King, G. L. / Insulin's effect on protein kinase C and diacylglycerol induced by diabetes and glucose in vascular tissues. In: American Journal of Physiology - Endocrinology and Metabolism. 1994 ; Vol. 267, No. 3 30-3.
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