Vascular protein metabolism in the pathogenesis of hypertension

Labelled proline incorporation into collagenous and noncollagenous proteins of aorta or mesenteric arteries was significantly increased in 70-day-old spontaneously hypertensive rats (SHR) at the early stage of hypertension in comparison with normotensive Wistar-Kyoto (WK) rats; however such an increase was not detected in 30-day-old SHR at the prehypertensive stage. Similar increases in the proline incorporation were noted in 70-day-old renal hypertensive rats and in DOCA hypertensive rats in which hypertension had been induced similarly to that om SHR. Furthermore, the decay of the specific activity of noncollagenous and collagenous proteins was studied for 100 days after labelled proline infusion. The dacay of the noncollagenous protein activity was clearly accelerated in the heart, aorta and especially in the mesenteric arteries of SHR compared with WK. The decrease in the hydroxyproline radioactivity of the collagenous protein was significantly faster in the aorta and mesenteric arteries in SHR. These results proved the increased protein metabolism in the arterial walls in the relatively early stage of hypertension in SHR as well as in experimental hypertension, and then suggested its importance in the common pathogenetic mechanisms of hypertension.