Rapid modulation of rat adipocyte lipoprotein lipase: effect of calcium, A23187 ionophore, and thrombin

Maurizio R. Soma, Antonio Gotto, Giancarlo Ghiselli

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The effect of calcium ions on the lipoprotein lipase (LPL) activity in rat adipocytes has been investigated. Incubation of the cells in the absence of extracellular calcium produced a rapid decline of LPL activity in the cells. The enzyme, however, could be immediately reactivated in less than 3 min by the addition of calcium. The degree of reactivation was proportional to the concentration of extracellular calcium. α1 agonists phenylephrine and methoxamine affected LPL activity only slightly, as did vasopressin and angiotensin II. In contrast, calcium ionophore A23187 elicited a quick and transient enzyme activation which reached its peak 4 min after the addition of the drug. Thrombin (0.1 U/ml) produced the most rapid and intense response. The effect of thrombin was already evident 10 s after its addition, and the enzyme activity almost doubled above the basal level. Extracellular calcium was necessary to achieve thrombin activation. Contrary to previous thought [1], these data support the conclusion that LPL may undergo rapid activation, and that calcium ions are critically involved in this activation process. Thrombin rapidly raises LPL activity and may be one of its physiological activators in vivo.

Original languageEnglish (US)
Pages (from-to)307-314
Number of pages8
JournalBiochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
Volume1003
Issue number3
DOIs
StatePublished - Jun 28 1989

Keywords

  • (Rat adipocyte)
  • Calcium
  • Enzyme activity
  • Ionophore A23187
  • Lipoprotein lipase
  • Thrombin

ASJC Scopus subject areas

  • Endocrinology
  • Biophysics
  • Biochemistry

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