ELEVATED BLOOD-PRESSURE IN SPONTANEOUSLY HYPERTENSIVE RATS CONSUMING A HIGH SUCROSE DIET IS ASSOCIATED WITH ELEVATED ANGIOTENSIN-II AND IS REVERSED BY VANADIUM

Objective To determine the changes in serum angiotensin II (Ang II) an d endothelin-1 levels induced by vanadium treatment of sugar-fed rats in order to investigate the relationship between changes in blood pres sure and Ang II and endothelin-1 levels, Methods Male spontaneously hy pertensive rats (SHR) were fed starch (control), sucrose, and sucrose plus vanadium compounds at various concentrations, The systolic blood pressure of the rats was estimated by tail-cuff plethysmography. Serum Ang II and endothelin-1 levels were measured by radioimmunoassay. Res ults There were increases in systolic blood pressure (by 8%) and in se rum Ang II (by 20%) in sucrose-fed SHR compared with control, In sucro se plus vanadium-fed SHR, the lowering of the systolic blood pressure (by 11-16% of the sucrose-fed value) was accompanied by a significant decrease in Ang II levels (by 25-60% of the sucrose-fed value) and an increase in endothelin-1 level (by 61-76% of the sucrose-fed value). C onclusion That Ang II levels are elevated in sucrose-induced hypertens ion and decreased after vanadium therapy suggests that the renin-angio tensin system plays a role in the induction of hypertension in this mo del, On the other hand, the elevation of endothelin-1 levels associate d with a decreased systolic blood pressure might be secondary to vanad ium stimulation of endothelial cells, The data suggest that endothelin -1 is not involved in sugar-induced elevations of the blood pressure.