INSULIN ENHANCES ANGIOTENSIN-II-INDUCED DNA-SYNTHESIS IN VASCULAR SMOOTH-MUSCLE CELLS OF THE RAT

Hypertension has a high prevalence among subjects with decreased insul in sensitivity and/or hyperinsulinemia. Furthermore, angiotensin II pl ays a pivotal role in the regulation of vascular tone and is known to induce hypertrophy and/or hyperplasia in vascular smooth muscle cells. In the present study, the effect of insulin on angiotensin II induced smooth muscle cell growth (Wistar-Kyoto rat) was investigated. Cell g rowth was assessed by the measurement of [H-3]thymidine incorporation into cell DNA. Insulin in a concentration range of 1.7 x 10(-10)-1.7 x 10(-6) M lacked any effect on cell DNA synthesis. However, insulin en hanced the angiotensin II induced DNA synthesis in a concentration-dep endent manner. This effect was similar in cells with a weak and in cel ls with a marked response in DNA synthesis to stimulation with 100 nM angiotensin II. In conclusion, insulin is able to enhance angiotensin II induced DNA synthesis and may therefore function as a growth cofact or in vascular smooth muscle cells.