抄録
Previous studies have shown the selectivity of epidermal growth factor (EGF), in promoting the growth of cultured vascular smooth muscle cells derived from spontaneously hypertensive rats (SHR) compared to cells derived from the normotensive counterpart strain, the Wistar-Kyoto (WKY) rats. We have now examined EGF binding to tissue membranes from intact animals. Using the membrane preparations isolated by differential centrifugation from kidney and aortic tissues of age-matched adult SHR and WKY rats, the specific maximal EGF binding was found to be higher in the SHR than the WKY rats. The EGF binding affinity, however, was similar in the two strains. Analysis of solubilized EGF receptor from the SHR and WKY rat kidney by SDS-polyacrylamide gel electrophoresis revealed no differences in molecular weight. Hydralazine treatment of both strains to chronically lower the blood pressure over a period of 8 weeks, did not significantly change the EGF binding in the kidney or aorta. The increased binding observed in SHR tissues, therefore, is not primarily attributable to increasing blood pressue. The immunoreactive urinary EGF in the hypertensive adult SHR, determined by radioimmunoassay, was about one half of that measured in age mached normotensive WKY rats. These studies lend support to the thesis that the observed increase in EGF binding sites in the kidney and aorta may be related to the putative genetic fault in SHR. (Hypertens Res 1992; 15: 93-98)
