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  1. Immunohistochemical characteristics of the hypophysis in normal conditions and chronic stress
    Kapitonova MY, Kuznetsov SL, Khlebnikov VV, Zagrebin VL, Morozova ZCh, Degtyar YV
    Neurosci. Behav. Physiol., 2010 Jan;40(1):97-102.
    PMID: 20012496 DOI: 10.1007/s11055-009-9217-4
    Quantitative immunohistochemical methods were used to assess activation of the hypothalamo-hypophyseal-adrenocortical system at the level of its central component - the adenohypophysis - in the growing body during chronic exposure to psychoemotional stressors of different strengths. Sprague-Dawley rats aged 30 days were subjected to "mild" or "severe" immobilization stress for 5 h per day for seven days. Animals were decapitated at the end of the last stress session and the endocrine glands (hypophysis, adrenals) were harvested, weighed, and embedded in paraffin; sections were stained with hematoxylin and eosin, and also immunohistochemically using monoclonal antibodies to adrenocorticotropic hormone (ACTH) and proliferating cell nuclear antigen (PCNA) following by automated image analysis. These studies showed that stress-associated hyperplasia of corticotropocytes in rats of pubertal age was due more to the differentiation of existing immature precursor cells than to cell proliferation.
    Matched MeSH terms: Adrenal Glands/metabolism*
  2. Fulltext LGR5 Activates Noncanonical Wnt Signaling and Inhibits Aldosterone Production in the Human Adrenal
    Shaikh LH, Zhou J, Teo AE, Garg S, Neogi SG, Figg N, et al.
    J Clin Endocrinol Metab, 2015 Jun;100(6):E836-44.
    PMID: 25915569 DOI: 10.1210/jc.2015-1734
    CONTEXT: Aldosterone synthesis and cellularity in the human adrenal zona glomerulosa (ZG) is sparse and patchy, presumably due to salt excess. The frequency of somatic mutations causing aldosterone-producing adenomas (APAs) may be a consequence of protection from cell loss by constitutive aldosterone production.

    OBJECTIVE: The objective of the study was to delineate a process in human ZG, which may regulate both aldosterone production and cell turnover.

    DESIGN: This study included a comparison of 20 pairs of ZG and zona fasciculata transcriptomes from adrenals adjacent to an APA (n = 13) or a pheochromocytoma (n = 7).

    INTERVENTIONS: Interventions included an overexpression of the top ZG gene (LGR5) or stimulation by its ligand (R-spondin-3).

    MAIN OUTCOME MEASURES: A transcriptome profile of ZG and zona fasciculata and aldosterone production, cell kinetic measurements, and Wnt signaling activity of LGR5 transfected or R-spondin-3-stimulated cells were measured.

    RESULTS: LGR5 was the top gene up-regulated in ZG (25-fold). The gene for its cognate ligand R-spondin-3, RSPO3, was 5-fold up-regulated. In total, 18 genes associated with the Wnt pathway were greater than 2-fold up-regulated. ZG selectivity of LGR5, and its absence in most APAs, were confirmed by quantitative PCR and immunohistochemistry. Both R-spondin-3 stimulation and LGR5 transfection of human adrenal cells suppressed aldosterone production. There was reduced proliferation and increased apoptosis of transfected cells, and the noncanonical activator protein-1/Jun pathway was stimulated more than the canonical Wnt pathway (3-fold vs 1.3-fold). ZG of adrenal sections stained positive for apoptosis markers.

    CONCLUSION: LGR5 is the most selectively expressed gene in human ZG and reduces aldosterone production and cell number. Such conditions may favor cells whose somatic mutation reverses aldosterone inhibition and cell loss.

    Matched MeSH terms: Adrenal Glands/metabolism*
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