Kinetic analysis of 1,2-diacylglycerol mass levels in cultured fibroblasts. Comparison of stimulation by α-thrombin and epidermal growth factor

T. M. Wright, L. A. Rangan, H. S. Shin, D. M. Raben

Research output: Contribution to journalArticlepeer-review

Abstract

We have examined the kinetics of 1,2-diacylglycerol production in quiescednt IIC9 fibroblasts. α-Thrombin and epidermal growth factor (EGF) both stimulate an increase in the mass of cellular 1,2-diacylglycerol. The generation of 1,2-diacylglycerol is biphasic when stimulated by a high concentration of α-thrombin (500 ng/ml), with an early phase peaking at 15 s and a late phase peaking at 5 min. Production of 1,2-diacylglycerol is monophasic when stimulated by: (a) a low concentration of α-thrombin (100 pg/ml); (b) a high concentration of α-thrombin added to cultures which had been pretreated with chymotrypsin; or (c) EGF. In all cases the stimulation of 1,2-diacylglycerol was sustained for at least 30 min. In a previous report (Raben, D. M., Yasuda, K., and Cunningham, D. D. (1987) Biochemistry 26, 2759-2765), it was demonstrated that α-thrombin stimulates lipid metabolism in fibroblasts via two coupling mechanisms designated R1 and R2. We now present evidence that the early phase of α-thrombin-stimulated 1,2-diacylglycerol production is related to R1, which is characterized by: 1) increased release of arachidonic acid, 2) hydrolysis of polyphosphoinositides, and 3) inhibition by pretreating cultures with chymotrypsin. The late phase is related to R2 which is characterized by 1,2-diacylglycerol production in the absence of stimulated phosphoinositide hydrolysis and arachidonic acid release. In addition, EGF activates an R2-like mechanism in that it does not stimulate the release of arachidonic acid or hydrolysis of polyphosphoinositides but does stimulate a 2-fold increase in 1,2-diacylglycerol mass.

Original languageEnglish (US)
Pages (from-to)9374-9380
Number of pages7
JournalJournal of Biological Chemistry
Volume263
Issue number19
StatePublished - 1988

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Kinetic analysis of 1,2-diacylglycerol mass levels in cultured fibroblasts. Comparison of stimulation by α-thrombin and epidermal growth factor'. Together they form a unique fingerprint.

Cite this