Insulin Resistance as a Determinant of Cardiovascular Reactivity
Bonita Falkner Sonia Hulman Harvey Kushner Hahnemann University
Essential hypertension (EH)is a health problem of major magnitude. Dysregulatory mechanisms evolving into hypertensive states have their onset in the young ( Londe, Bourgoigne, Robson, & Goldring, 1971; Task Force on Blood Pressure Control in Children, 1977; Zinner, Levy, & Kass, 1971). Investigations in the young have characterized level of blood pressure, identified related parameters ( Cornoni-Huntley, Harlan, & Leaverton, 1979; Harlan, Cornoni-Huntley, & Leaverton, 1979; Prineas, Gillum, Horibe, & Hannan, 1980), and provided evidence of hemodynamic changes in the young at risk for EH ( Falkner, Lowenthal, Affreme, & Hamstra, 1982; Schieken, Clark, & Lauer, 1981; Zahka, Neill, Kidd, Cutilleta, & Cutilleta, 1983).
One line of investigation has concerned the sympathetic nervous system ( Folkow, 1982). There is a correlation of stress-induced enhanced sympathetic nervous system activity in EH ( Baumann et al., 1973; Nestle, 1969) and in the young with a family history of EH ( Falkner, Onesti, Angelakos, Fernandez, & Langman, 1979; Manuck, & Proietti, 1982). Based on the experimental design of these studies, it has been assumed that the neurogenic hyperresponsivity has been related to greater beta-adrenergic activity. However, many of the clinical studies on neurogenic-cardiovascular interaction have used racially mixed populations. Fredrickson ( 1986) compared racial differences in cardiovascular reactivity to mental stress in EH. He observed that although the Black sample was small, compared to Whites, Blacks had lesser cardiac sympathomimetic responses but had greater vascular responses to mental stress. Light and Obrist ( 1980) have investigated the racial differences in the cardiovascular response to active coping