Wenzel, Jan, Grabinski, Nicole, Knopp, Cordula A., Dendorfer, Andreas, Ramanjaneya, Manjunath, Randeva, Harpal S., Ehrhart-Bornstein, Monika, Dominiak, Peter and Joehren, Olaf (2009) Hypocretin/orexin increases the expression of steroidogenic enzymes in human adrenocortical NCI H295R cells. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, Vol.297 (No.5). R1601-R1609. doi:10.1152/ajpregu.91034.2008 ISSN 0363-6119.

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Abstract

Wenzel J, Grabinski N, Knopp CA, Dendorfer A, Ramanjaneya M, Randeva HS, Ehrhart-Bornstein M, Dominiak P, Johren O. Hypocretin/orexin increases the expression of steroidogenic enzymes in human adrenocortical NCI H295R cells. Am J Physiol Regul Integr Comp Physiol 297: R1601-R1609, 2009. First published September 30, 2009; doi: 10.1152/ajpregu. 91034.2008.-Hypocretins/orexins act through two receptor subtypes: OX1 and OX2. Outside the brain, orexin receptors are expressed in adrenal glands, where orexins stimulate the release of glucocorticoids. To further address the regulation of steroidogenesis, we analyzed the effect of orexins on the expression of steroidogenic enzymes in human adrenocortical National Cancer Institute (NCI) H295R cells by qPCR. In NCI H295R cells, OX2 receptors were highly expressed, as they were in human adrenal glands. After treatment of NCI H295R cells with orexin A for 12-24 h, the cortisol synthesis rate was significantly increased, whereas 30 min of treatment showed no effect. While CYP11B1 and CYP11B2 mRNA levels were increased already at earlier time points, the expression of HSD3B2 and CYP21 mRNA was significantly up-regulated after treatment with orexin A for 12 h. Likewise, orexin B increased CYP21 and HSD3B2 mRNA levels showing, however, a lower potency compared with orexin A. The mRNA levels of CYP11A and CYP17 were unaffected by orexin A. OX2 receptor mRNA levels were down-regulated after 12 and 24 h of orexin A treatment. Orexin A increased intracellular Ca2+ but not cAMP concentrations in NCI H295R cells. Furthermore, inhibition of PKC and MAPK kinase/ERK kinase (MEK1/2) prevented the increase of HSD3B2 expression by orexin A. Accordingly, orexin A treatment of NCI H295R cells markedly enhanced ERK1/2 phosphorylation that was prevented by PKC and, in part, PKA inhibition. In conclusion, orexins may influence adrenal steroidogenesis by differential regulation of the expression of steroidogenic enzymes involving Ca2+, as well as PKC-ERK1/2 signaling.

Item Type:	Journal Article
Subjects:	Q Science > QP Physiology
Divisions:	Faculty of Science, Engineering and Medicine > Medicine > Warwick Medical School > Biomedical Sciences > Translational & Experimental Medicine > Metabolic and Vascular Health (- until July 2016) Faculty of Science, Engineering and Medicine > Medicine > Warwick Medical School
Journal or Publication Title:	American Journal of Physiology: Regulatory, Integrative and Comparative Physiology
Publisher:	American Physiological Society
ISSN:	0363-6119
Official Date:	November 2009
Dates:	Date Event November 2009 Published
Volume:	Vol.297
Number:	No.5
Number of Pages:	9
Page Range:	R1601-R1609
DOI:	10.1152/ajpregu.91034.2008
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access

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