Vanadate-Stimulated Release of Hepatic Lipase Activity from Liver

抄録

Vanadate stimulated the release of rat hepatic lipase activity from liver slices into an incubation medium in a time- and dose-dependent manner. Insulin, however, failed to have this stimulatory action, and the release by heparin was recognized, but was not additive to that by vanadate. Amiloride, an inhibitor of tyrosine kinase in some receptors and of the Na⁺/H⁺ exchange system suppressed the vanadate-stimulated releaes. Biochanin A, a different type of tyrosine kinase inhibitor than amiloride, also suppressed the effect of vanadate. HTe stimulation by vanadate was clearly preserved in Na⁺-, K⁺-, or Ca²⁺-free medium, suggesting that neither the Na⁺/H⁺ exchange system, Na⁺, K⁺-adenosine triphosphatase, nor Ca²⁺-influx into cells is involved in the action of this substance. These results suggest that vanadate-stimulated releaes of the enzyme activity is associated with the activation of the tyrosine kinase activity.