Expression of the beacon gene in the rat adrenal gland: direct inhibitory effect of beacon[47-73] on aldosterone secretion from dispersed adrenal zona glomerulosa cells

Beacon gene was recently identified in the rat hypothalamus, and there is evidence that beacon may be involved in the functional regulation of neuroendocrine axes. Reverse transcription-polymerase chain reaction and immunocytochemistry showed the expression of beacon mRNA and protein in the rat adrenal gland, especially in the cortex. Beacon[47-73], at a concentration over 10(-7) M decreased basal aldosterone secretion from dispersed rat zona glomerulosa (ZG) cells, without affecting the ACTH-stimulated one. Basal and agonist-stimulated corticosterone secretion from dispersed zona fasciculata-reticularis cells and catecholamine release from adrenomedullary slices were unaffected by beacon[47-73]. The suppressive effect of beacon[47-73] on aldosterone secretion from ZG cells was abolished by either H-89 or calphostin-C, which are inhibitors of protein kinase A and C signaling cascades. Taken together, these findings allow us to suggest that beacon can be included in the group of regulatory peptides involved in the fine tuning of ZG secretory activity.