Insulin-induced hypoglycemia in conscious dogs: effect of maintaining carotid arterial glucose levels on the adrenocorticotropin, epinephrine, and vasopressin responses.

Abstract

The purpose of this study was to determine the role of central hypoglycemia in the regulation of the ACTH, vasopressin, and epinephrine responses to insulin administration. In each of six conscious dogs with carotid loops, saline or glucose was infused into both carotid arteries following the injection of 0.025,0.10, or 0.50 U insulin/kg. Intracarotid glucose infusion prevented a fall in superior vena caval glucose concentrations, despite peripheral hypoglycemia as measured by inferior vena caval (IVC) glucose concentrations. Intracarotid glucose infusions attenuated the ACTH and epinephrine responses to hypoglycemia. The logarithm of the peak plasma ACTH concentrations was related to the logarithm of the nadir in the IVC glucose concentrations during both intracarotid saline and glucose infusions, but intracarotid glucose infusions reduced the magnitude of the peak ACTH response for a given nadir in glucose by an average of 65%. The ACTH responses over the 40- to 60-min experimental periods for moderate ...