The relationship between perfusion medium flow rate and steroid secretion in the isolated perfused rat adrenal gland in situ

Abstract

Using the in-situ, isolated, perfused rat adrenal preparation, we have investigated the effects of changes in the rate of perfusate flow through the gland, brought about both mechanically and by the use of vasoactive agents, in the absence of known adrenocortical stimulants. Adenosine caused a significant increase in the rate of perfusate flow through the adrenal, with a concomitant rise in corticosterone, but not aldosterone, secretion. Adrenaline, on the other hand, caused a decrease in the rate of perfusate flow through the gland, accompanied by a decrease in the rate of steroid secretion. Furthermore, increases in the rate of delivery of perfusate to the gland, brought about by increasing the peristaltic pump rate, caused a large increase in corticosterone secretion, although aldosterone was unaffected. Neither adenosine nor a mechanically increased rate of perfusate delivery increased steroid secretion by collagenase-dispersed rat adrenocortical cells superfused on a Sephadex column. These results suggest the existence of hitherto unsuspected intraglandular mechanisms for the control of steroid secretion.

Vascularization of the adrenal cortex: its possible involvement in the regulation of steroid hormone release

“…This change in flow rate is believed to result from the interaction of ACTH and mast cells, located in the general capsular region near the afferent arterioles (Hinson et al, 1989). ACTH stimulation of the mast cells results in the local release of the vasoactive substances, histamine and serotonin (Hinson et al, 1986a), which have also been shown to increase the perfusion flow rate within the isolated perfused adrenal gland (Hinson et al, 1989). These vasoactive substances are thus believed to exert a direct vasodilatory effect upon the arteriolar component of the adrenal vasculature.…”

Morphological and functional studies of the paracrine interaction between cortex and medulla in the adrenal gland

“…In the rat adrenal, the rate of glucocorticoid secretion is closely linked to the rate of blood flow through the adrenal gland (Hinson et al, 1986;Vinson and Hinson, 1992). There is evidence that adrenal blood flow may be regulated in part by neuropeptides like VIP, substance P, NPY, neurotensin, Met-enkephalin, and Leu-enkephalin released from the capsular region of the adrenal gland in response to splanchnic nerve stimulation .…”

“…The documentation of the exocytosis process of a chromaffin vesicle from a chromaffin cell, which was in direct contact with a cortical cell, constituted the first direct proof of a paracrine action of a chromaffin cell upon an adrenocortical cell. Furthermore, it was shown that the cells inside the adrenal cortex are linked by gap junctions (Black et al, 1979;Hinson et al, 1986;Nussdorfer, 1986;Vinson and Hinson, 1992). Using an interactive laser-cytometer, it was shown that functionally intact gap junctions reform among adrenocortical cells in culture (Usadel et al, 1993).…”

Angiotensin II Relaxations of Bovine Adrenal Cortical Arteries

“…Increases in adrenal flow alone can stimulate steroid hormone release. 14 Increased vascular resistance of adrenal cortical arteries restricts blood flow and decreases adrenal hormone release. In isolated bovine small cortical arteries, Ang II causes a biphasic response on vascular diameter.…”