ELEVATED EPIDERMAL GROWTH-FACTOR RECEPTOR LEVELS IN HYPERTENSIVE LYONRAT-KIDNEY AND AORTA

1. The adult spontaneously hypertensive Lyon rats (LH strain) exhibite d increased maximal epidermal growth factor (EGF) binding in freshly p repared kidney and aortic tissue membranes compared with age-matched n ormotensive (LN) or hypotensive (LL) strains. However, the binding aff inity of the receptors to EGF was the same in all the three strains st udied. These findings indicate an increased number of EGF receptors (E GFR) in the hypertensive LH strain. 2. Protein tyrosine kinase activit y associated with the EGFR was also elevated in the LH strain compared with LN or LL strains, indicating that these receptors are functional ly active. 3. There was a correlation between maximal EGF binding by a ortic membranes and blood pressure in individual animals (r = 0.55; P < 0.001). 4. Taken together with previously reported similar findings in other models of genetic hypertension, the present results suggest a possible role for increased levels of EGFR in the development and mai ntenance of genetic hypertension.