Effects of Angiotensin-II On Inositol Phosphate Accumulation And Calicum Influx in Bovine Adrenal And Y–1 Tumor Adrenal Cells

Abstract

The present study compared the action of angiotensin II (A-II) in bovine adrenal fasciculata cells (BA) and Y–1 adrenal tumor cells which are sensitive and resistant respectively to its steroidogenic effect. In both models, A-II induced a time and dosedependent inositol phosphate (Ins-Ps) accumulation and calcium influx. However, in Y–1 cells the Ins-Ps production was low and only Ins-P₁ and Ins-P₂ were accumulated. The calcium influx in BA cells was observed after 15 seconds and remained linear as long as the hormone was present, whereas in Y–1 cells calcium influx started prior the 15 seconds and reverted to basal values after 45 seconds. The effects of A-II antagonists. Taken together these results demonstrate the presence of functional A-II receptors in both cell types which are coupled to the two main intracellular messenger systems. Thus, the A-II steroidogenic refractoriness of Y–1 cells is probably related to some alteration(s) located beyond the calcium and/or protein kinase C A-II-messenger system.