[en] Angiotensin II (ANG) stimulates the hydrolysis of phosphatidylinositol bisphosphate with the consequent formation of inositol trisphosphate and diacylglycerol in cultured smooth muscle cells derived from rat aorta. They have observed the effects of ANG on protein and DNA synthesis by measuring the incorporation of ³H-leucine and ³H-thymidine, respectively, into acid-precipitable material. Aortic muscle cells were grown to confluence in medium containing 10% fetal bovine serum (FBS) and incubated for 24 hours in serum-free medium to arrest growth. Then fresh serum-free medium was added with the following additions: ANG (100 nM), insulin (2 μg/ml), or 10% FBS. After an additional 24 hours the cells were pulse labeled for 30 min with either ³H-leucine or ³H-thymidine. FBS increased ³H-leucine incorporation by -2.5 fold and ³H-thymidine incorporation by 7-10 fold. ANG or insulin increased ³H-leucine incorporation by 40-50%, and the combination of ANG and insulin was nearly as effective as 10% FBS. ANG stimulated ³H-thymidine incorporation by -2.5 fold. Insulin, which was less effective than ANG, increased ³H-thymidine incorporation by about 50%. ANG and insulin added together synergistically increased ³H-thymidine incorporation by 5-6 fold. An ANG antagonist, Sarl,leu8-ANG, at 2 μM markedly decreased ³H-thymidine incorporation in the presence of ANG and insulin