1. The level of DNA repair synthesis has been compared in males diagnosed as having hypertension (diastolic blood pressure ≥ 100 mmHg), males with slightly elevated blood pressure (>95th percentile corrected for age) and males with normal or subnormal blood pressure (≤30th percentile corrected for age).
2. The hypertensive males and the males with elevated blood pressure could not be distinguished from each other with respect to the levels of chemically induced repair synthesis, but both were significantly increased over the induced repair synthesis values of individuals with normal or low blood pressure. Since it has been shown previously that lymphocytes with high repair synthesis values also have increased levels of both carcinogen-DNA binding and chromosomal aberrations (Nordén, Scherstén, Thulin, Pero, Bryngelsson & Mitelman, 1975), the biological significance of this variable appears to be of value in discriminating between normal and high blood pressure groups.