Immunohistochemical analysis of AT1 receptor versus P450c17 and 3βHSD expression in ovine adrenals

Ian M. Bird, Jing Zheng, C. Jo Corbin, Ronald R. Magness, Alan J Conley

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Previous studies in ovine adrenocortical cells in vitro have shown angiotensin II (AII) receptors are expressed on the zona fasciculata (ZF) cells and are functionally coupled to phosphoinositidase C and increased [Ca2+](i), but AII stimulation does not cause an acute change in cortisol biosynthesis. AII can, however, chronically regulate differential expression of P450c17 and 3βHSD in ovine adrenocortical cells in vitro. We have stained ovine adrenal sections with specific antisera to the angiotensin II Type-1 receptor (AT1-R), as well as P450c17 and 3βHSD in order to further test the hypothesis that changes in AT1-R expression underlie changes in zonal expression of P450c17 and 3βHSD in vivo. AT1-R expression was found to be highest in the outermost layer of cells (zona glomerulosa, ZG) which stained negatively for P450c17 and only faintly positive for 3βHSD, as expected. The adjacent layer of cells (ZF) stained much less strongly for AT1-R but stronger for P450c17 and 3βHSD. These findings are consistent with our previously reported in vitro expression data, and suggest that the transition from ZG to ZF phenotype, i.e. increased P450c17 and 3βHSD expression, may require reduced expression of AT1-R, but maintenance of reduced levels of AT1-R expression in the ovine ZF still allows for differential control of the P450c17: 3βHSD ratio. Thus, even though there is no acute cortisol response to AII alone in these cells, AII stimulation can oppose C19 steroid production in the face of cortisol biosynthesis by the ZF in response to agonists such as ACTH.

Original languageEnglish (US)
Pages (from-to)349-353
Number of pages5
JournalEndocrine Research
Volume22
Issue number4
StatePublished - 1996

ASJC Scopus subject areas

  • Endocrinology

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