Characterization and localization of lipocortin 1-binding sites on rat anterior pituitary cells by fluorescence-activated cell analysis/sorting and electron microscopy.

Christian, H; Taylor, A; Flower, R; Morris, J; Buckingham, J

Journal article

Characterization and localization of lipocortin 1-binding sites on rat anterior pituitary cells by fluorescence-activated cell analysis/sorting and electron microscopy.

Abstract:: Lipocortin 1 (LC1) is an important mediator of glucocorticoid action in the anterior pituitary gland, where it appears to act via cell surface binding sites to suppress peptide release. We have exploited a combination of fluorescence-activated cell (FAC) analysis/sorting and electron microscopy to detect, characterize, and localize LC1-binding sites on the surface of dispersed rat anterior pituitary cells, using human recombinant LC1 (hu-r-LC1) as a probe. High affinity (Kd = 14 +/- 3 nM) hu-r-LC1-binding sites were detected on approximately 80% of anterior pituitary cells dispersed with collagenase. The binding characteristics of the ligand resembled those observed in leukocytes, in that it was saturable; concentration, Ca2+, and temperature dependent; and abolished by trypsin. Functional studies demonstrated an excellent correlation between the presence of the cell surface binding protein and the capacity of an anti-LC1 monoclonal antibody to abrogate the inhibitory actions of dexamethasone (10 nM) on the release of ACTH initiated in vitro by CRH-41 (1 nM). Morphological analysis of cells harvested by FAC sorting showed that 1) somatotrophs, corticotrophs, lactotrophs, thyrotrophs, and gonadotrophs were all included in the population expressing LC1 binding sites; and 2) the LC1-binding sites assume a punctate distribution across the cell surface. These data show that anterior pituitary cells express high affinity surface LC1-binding protein(s); they thus provide further evidence for a specific membrane mechanism of action of LC1 in regulating the endocrine function of the anterior pituitary.

Publication status:: Published

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APA Style

Christian, H., Taylor, A., Flower, R., Morris, J., & Buckingham, J. (1997). Characterization and localization of lipocortin 1-binding sites on rat anterior pituitary cells by fluorescence-activated cell analysis/sorting and electron microscopy. Endocrinology, 138(12), 5341–5351.

MLA Style

Christian, H, et al. “Characterization and Localization of Lipocortin 1-Binding Sites on Rat Anterior Pituitary Cells by Fluorescence-Activated Cell Analysis/Sorting and Electron Microscopy.” Endocrinology, vol. 138, no. 12, 1997, pp. 5341–51.

Chicago Style

Christian, H, A Taylor, R Flower, J Morris, and J Buckingham. 1997. “Characterization and Localization of Lipocortin 1-Binding Sites on Rat Anterior Pituitary Cells by Fluorescence-Activated Cell Analysis/Sorting and Electron Microscopy.” Endocrinology 138 (12): 5341–51.
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