RESUMO
Functional angiotensin receptors were characterized in the rat pancreatic acinar cell line AR4-2J. Angiotensin II stimulated a dose-dependent release of amylase and production of inositol phosphates. Results of high-performance liquid chromatography separation of inositol phosphates indicated that angiotensin stimulated the rapid accumulation of inositol 1,3,4-trisphosphate. Angiotensin II and angiotensin III were at least an order of magnitude more potent than angiotensin I in the stimulation of amylase release. The angiotensin II-stimulated amylase release was blocked by losartan, a selective AT1 angiotensin antagonist. The selective AT2 angiotensin receptor ligands CGP42112 did not alter angiotensin II-stimulated amylase released. However, CGP42112 stimulated amylase release at micromolar concentrations with a potency similar to angiotensin I. Analysis of mRNA expression by reverse transcription polymerase chain reaction suggested that AT1A was the predominant type-I angiotensin receptor expressed in the AR4-2J cells.
