The increase of platelet production was demonstrated in stroke-prone SHR(SHRSP) after 10 weeks of age, probably due to increased platelet consumption compared with those in stroke-resistant SHR(SHRSR)(Koganemaru, S., et al. Thrombus. Haemostas.(Stuttgart)38:139, 1977). We extended our study to see the effect of aging, blood pressure, platelet-inhibiting drug and vitamin E(Vit.E) on this kinetic change. SHRSP(A1-sbF37-39) and SHRSR (BlF36-38) with matched age (5 weeks, 10 weeks and 9-12 months) and sex were used. The maximum uptake of 75se-methionine(75SeM) into platelets was not affected in both salt loading group and Clonidine group in SHRSP. A significant decrease was observed in dipyridamole group (0.096 ± 0.020, p<0.05). The platelet survival time was shortened in Vit. E deficient group of SHRSR; 3.0 days at 9-10 weeks. In Vit.E sufficient group of SHRSP. the platelet survival time was corrected to normal. The maximum uptake of 75SeM increased in both Vit.E deficient group of SHRSP (0.119 ± 0.010 vs 0.192 ± 0.030, p<0.01) and SHRSR (0.071 ± 0.016 vs 0.119 ± 0.018, p<0.01). The increased platelet production was not affected by blood pressure but it can be suppressed by treating with dipyridamole or giving Vit.E before 10 weeks of age.
Effect of regression of cardiac hypertrophy on ischemic myocardial damage in spontaneously hypertensive rats.