Hostility, Race, and Glucose Metabolism in Nondiabetic Individuals

OBJECTIVE— The present study was designed to determine whether hostility is differentially related to measures of glucose metabolism in African-Americans and Caucasians. RESEARCH DESIGN AND METHODS— The relationship of hostility, as measured by a subset of the Cook-Medley hostility scale (CMHOST) inventory items, to various parameters of glucose metabolism were examined in a young, healthy sample of male and female African-American and Caucasian volunteers. Fasting blood samples were collected during an inpatient admission, at which time the CMHOST was also administered. RESULTS— In the entire sample, the CMHOST was found to be significantly correlated with fasting glucose and insulin sensitivity, as measured by the homeostatic model assessment (HOMA). However, the relationship of hostility to these parameters of glucose metabolism was different in African-American and Caucasian subjects. Hostility was significantly related to fasting glucose in African-Americans and to insulin sensitivity and fasting insulin in Caucasian subjects. The relationship of hostility to insulin sensitivity and fasting insulin was partially dependent on BMI in Caucasians, but the relationship of hostility to fasting glucose was unrelated to BMI in African-Americans. CONCLUSIONS— Our data suggest that the relationship of hostility to measures of glucose metabolism is mediated differently in these two ethnic groups. Therefore, hostility seems to be part of a constellation of risk-related behaviors related to BMI in Caucasians but independently related to fasting glucose in African-Americans

Altered pituitary hormone response to naloxone in hypertension development.

Endogenous opioid regulation of blood pressure is altered during stress in young adults at risk for hypertension. We studied the effects of the opioid antagonist naloxone on the secretion of corticotropin and /3-endorphin during psychological stress in young adults with mildly elevated casual arterial pressures. Naloxone-induced secretion of both corticotropin and 0-endorphin was significantly diminished in persons at enhanced risk for hypertension compared with the low blood pressure control group. Results suggest that opioidergic inhibition of anterior pituitary function is altered in hypertension development. {Hypertension 1989;14:636-644) Endogenous opioids interact with circulatorycontrol nuclei at several distinct anatomicsites, including adrenal medullae and periph-eral sympathetic ganglia,1-2 nucleus tractus soli-tarius,3 and hypothalamic paraventricular nuclei.4-5 This multiplicity of pathways results in pressor or depressor actions of opioid antagonists, depending on the dose, site of action, behavioral state, and the species under investigation.6-8 Recent work with the stereospecific opioid antagonist naloxone sug