Abstract
Summary
Lumboadrenal vein blood was continuously collected at min intervals from anesthetized dogs who were either made hypoxic or infused with ACTH or MEC. The secretions of 11-OHCS increased within the first min and attained peak rates between 5 and 10 min of exposure to these agents. Part of the increased secretory rates of the hypoxic and MEC groups could be accounted for by increases in adrenal blood flow. These data suggest that a min is sufficient time for hypoxia to (a) activate the hypothalamo–hypophyseal complex to release ACTH, (b) decrease the transit time for ACTH to reach the adrenal gland, and (c) increase adrenal blood and plasma flows. When occurring simultaneously, these 3 factors result in a rapid and sustained increase in adrenocortical secretory rates during hypoxia.
The excellent technical assistance of E. Blomquist, C. Lau and L. Malasanos is greatly appreciated. Special thanks are due Dr. G. Courtney for encouragement, assistance and discussions during the course of this investigation.
Get full access to this article
View all access options for this article.