Effects of neuromedin-U on immature rat adrenocortical cells: In vitro and in vivo studies

Abstract

Abstract. Neuromedin U (NMU) is a brain-gut peptide, that in the peripheral organs and tissues acts via a G protein-coupled receptor, called NMUR1. Reverse transcription-polymerase chain reaction showed the expression of NMUR1 mRNA in either cortex and medulla or dispersed zona glomerulosa and zona fasciculata-reticularis cells of the immature rat adrenals. Accordingly, immunocytochemistry demonstrated the presence of NMUR1-like immunoreactivity in the cortex and medulla of immature adrenals. NMU8 administration to immature rats was found to raise aldosterone, but not corticosterone, plasma concentration, without altering adrenal growth. Conversely, the exposure to NMU8 markedly enhanced the proliferative activity of immature rat inner adrenocortical cells in primary in vitro culture, without significantly affecting their corticosterone secretion. Collectively, our findings suggest that adrenals of immature rats may be a target for circulating NMU. However, the physiological significance and relevance of the adrenal effects of NMU remain to be ascertained.

Neuromedins U and S involvement in the regulation of the hypothalamo–pituitary–adrenal axis

“…In subsequent searches for mode of NMU action on corticosteroid secretion our group found that NMU had no effect on basal and ACTH-stimulated corticosterone secretion by freshly isolated or cultured inner zone adrenocortical cells, nor did it change their cytosolic Ca 2+ concentration (Malendowicz et al, 1994b; confirmed by Ziolkowska et al, 2008). However, this neuropeptide stimulated corticosterone output by adrenal slices, but not by fragments of adrenocortical autotransplants lacking medullary chromaffin cells (Malendowicz et al, 1994a).…”

“…In immature rat adrenal NMUR1 was expressed at both mRNA and protein (immunohistochemistry) levels while the signal from NMUR2 was absent. NMUR1 mRNA was detected in all adrenocortical zones and in medulla of the gland (Ziolkowska et al, 2008). Moreover, the presence of NMUR1 mRNA in isolated zona glomerulosa and fasciculata/reticularis cells rules out the possibility that the expression was due to the presence in the specimens assayed of the non-parenchymal components of the gland.…”

Visinin-like peptide 1 in adrenal gland of the rat. Gene expression and its hormonal control

“…Method of culturing rat adrenocortical cells was described earlier [61]. Briefly, adrenals were obtained from 20 to 22 days old rats.…”

Cerebellin and des-cerebellin exert ACTH-like effects on corticosterone secretion and the intracellular signaling pathway gene expression in cultured rat adrenocortical cells - DNA microarray and QPCR studies

“…Details of primary adrenocortical cell culture were published previously (20)(21)(22)(23)(24)(25)(26)(27)(28). Briefly, for the preparation of one primary culture of adrenocortical cells, 12 rats were sacrificed by decapitation.…”