HETEROGENEITY OF VASCULAR DNA-SYNTHESIS IN RESPONSE TO THE DEVELOPMENT OF GOLDBLATT 2-KIDNEY, ONE-CLIP HYPERTENSION

Objective: To examine the changes in the rate of DNA synthesis in the aorta and mesenteric and subcutaneous resistance arteries during the d evelopment of renovascular hypertension. Methods: Goldblatt two-kidney , one clip hypertensive and sham-operated control rats were studied 3, 7, 14 and 28 days after surgery. DNA synthesis was measured as the ho urly rate of [H-3]-thymidine incorporation into the DNA. Results: Thre e days after renal artery constriction there was a significant increas e in the DNA synthesis in both the aorta and the mesenteric vessels, a lthough the blood pressure was not changed. DNA synthesis was elevated during the development of hypertension, but returned to control level s after 28 days when the blood pressure had reached a plateau. By cont rast, there was no increase of DNA synthesis in the subcutaneous vesse ls at any time after renal artery constriction. The plasma renin conce ntration also was increased after 3 days in the clipped rats and remai ned elevated throughout the study. There were no significant changes i n the blood pressure, the plasma renin concentration or the rate of va scular DNA synthesis in the sham-operated control rats. Conclusions: T hese data indicate that there are regional differences in the vascular response to the induction of renovascular hypertension and that in so me vascular beds an increase in DNA synthesis precedes the rise in blo od pressure.