EFFECT OF ISOLATED PLA₂ ISOLATED FROM THE Crotalus durissus collilineatus ON THE INSULIN SECRETION OF RODENTS

NOGUEIRA, T.C.A.(1), FERREIRA, F(1), FILIPUTTI, E.(1), TOYAMA, M.H.(2), MARANGONI, S.(2), BOSCHERO, A.(1), CARNEIRO, E.M.(1)

(1)Department of Physiology and Biophysics, (2)Department of Biochemistry, Institute of Biology, State University of Campinas.

Objectives: Physiological action evaluation of isolated PLA₂ on isolated B-cells of Langerhans. Material and Methods: The isolated islets were incubated with toxins in presence of 2.8 mMand 16.7 mM of glucose as well as 30mM of potassium.  After each protocol the insulin quantification was made to evaluate the action of toxin.  At 2.8mM of glucose the isolated toxin (5.6mg/ml) increased 4.9 folds the insulin secretion but in 16.7 mM of glucose this increasing was 1.9 fold higher than to control (p<0.05).  In potassium presence only the isolated PLA₂ increase 4 fold the insulin secretion (p<0.05).  This toxin in 16.7 mMof glucose also significantly stimulated the calcium intake in 3.3 fold to than 16.7 mM of glucose but did not affected the glucose metabolism of isolated B-cells. In presence of Tetrodotoxin(TTX) or nifedipine did not change the increasing of insulin secretion induced by PLA₂ as well as the Dexamethasone or incubation of PLA₂ with heparin.  Yet when the islet was incubated with heparin, the insulin secretion stimulated by PLA₂ in presence of glucose 16.7 was partially inhibited. Conclusion: The isolated PLA₂ induce a insulin secretion independently of the B-cells stimulation (Glucose 2.8) and can be involved with intake calcium.

CORRESPONDENCE TO:

NOGUEIRA, T.C.A., Department of Physiology and Biophysics, Institute of Biology, State University of Campinas, Campinas, SP, Brasil, Email: tcan@bol.com.br