Presence of renin secretory granules in rat adrenal gland and stimulation of renin secretion by angiotensin II but not by adrenocorticotropin.

Abstract

Renin has been identified biochemically and immunohistochemically in the adrenal gland. We examined the subcellular distribution and behavior of adrenal renin. By differential centrifugation of adrenal capsules, we found renin mainly in mitochondrial fractions. By Percoll density gradient centrifugation of this fraction, dense granules were separated from mitochondria and microsomes. The renin activity in the dense granules from the capsules of nephrectomized rats was 15 times greater than that of the intact rat. Immunohistochemical studies revealed that the dense granules increased in number after bilateral nephrectomy. Immunogold staining of these granules showed unequivocally the presence of renin in these granules. Adrenal capsules in organ culture were found to release renin at a steady rate. Renin release from bilaterally nephrectomized rat adrenals was 46 times faster than from the organs of intact animals. The mechanism of the control of renin secretion from the adrenal gland was different from the kidney in that the secretion was stimulated by potassium chloride (10 mM) or angiotensin II (10--10-M) but not by ACI'H (10-9-10-7 M), suggesting stimulation by intracellular calcium. These results provide evidence that the adrenal synthesizes renin, stores it in specific secretory granules and secretes it in a regulated manner.

Increased adrenal renin in transgenic hypertensive rats, TGR(mREN2)27, and its regulation by cAMP, angiotensin II, and calcium.

“…The findings of Mizuno et al and Yamaguchi et al (9,28) speak in favor ofthe second possibility. Most likely, the specific apparatus ofthe cell type (e.g., endocrine cells, juxtaglomerular cells, submandibular gland cells) define in part the pattern of renin regulation.…”

“…Mizuno et al (9) isolated renin-containing secretory granules from the rat adrenal cortex and demonstrated that their number is increased by nephrectomy, a maneuver that is known to increase the adrenal renin content. They, and Yamaguchi et al (28), also suggested a stimulatory long-term effect of ANGII on renin secretion from rat adrenal cortical primary cell cultures.…”

“…The description of modified smooth muscle cells in the adrenal capsule with a similarity to kidney juxtaglomerular cells by Goormaghtigh and Handovsky (8), and the demonstration ofrenin secretory granules by Mizuno et al (9), suggest the possibility of regulated secretion of adrenal renin. Little data, however, are available for studying acute regulation of adrenal renin release.…”

Regulation of human renin expression in chorion cell primary cultures.

“…The control of renal renin release by p-adrenergic stimulation (presumably via cAMP) and the increase in rat adrenal renin content in response to calcium ion (37,38) could be due in part to increases in renin mRNA. By contrast, calcium ion may act by a different mechanism in the kidney, where it inhibits renal renin release (39) (10,31) (42) and that the spatial relationship of factor binding sites in the first 100 bp of the renin promoter is important for this stimulation.…”

Transcription of (pro)renin mRNA in the rat adrenal cortex, and the effects of ACTH treatment and a low sodium diet

“…Further evidence for the adrenal production of renin comes from in vitro studies using adrenal capsular tissue explants (Shier et al 1989) or rat adrenal glomerulosa cell cultures (Yamaguchi et al 1990). Mizuno et al (1988) suggested that renin is stored in the rat adrenal gland and that storage granules are released into the extracellular space in the same fashion as from the granules of the juxtaglomerular cells of the kidney.…”