PMID: 9549048Apr 29, 1998Paper

Recruitment of individually (all-or-none) responding cells, rather than amplitude enhancement, is the single-cell mechanism subserving the dose-responsive activation of intracellular calcium second messenger signaling by the human luteinizing-hormone receptor

Endocrine
F SunJ D Veldhuis

Abstract

We have investigated at the single-cell level how the human LH receptor mediates a dose-responsive increase in intracellular free calcium-ion concentrations ([Ca2+]i). In human embryonic kidney cells (293 cells) stably transfected with the full-length human LH receptor cDNA. Intact dimeric LH, but not LH beta- or alpha-subunits, evoked specific [Ca2+]i signals. High-resolution fluorescence (fura-2) video-microscopy demonstrated cell-to-cell variability in [Ca2+]i signaling responses in individual cells, viz., an all-or-none spike (9%), spike-and-plateau (25%), or plateau (52%) types of temporal signal. Oscillatory [Ca2+]i responses were observed in 12-14% of LH-stimulated cells unrelated to LH concentration. The LH dose-response originated by higher concentrations of LH recruiting more individually responding cells (rather than altering [Ca2+]i signal amplitude), and eliciting a [Ca2+]i rise more rapidly, i.e., at reduced latency. Cobalt did not abolish the LH-stimulated [Ca2+]i spike-and-plateau response, but decreased the percentage of cells with a plateau pattern. Quench experiments demonstrated influx of Mn2+ following the [Ca2+]i spike, thus directly documenting divalent cation inflow during the plateau phase. Adenylyl-cyc...Continue Reading

References

Oct 1, 1991·Molecular and Cellular Endocrinology·J A FloresD A Leong
Sep 30, 1985·Biochemical and Biophysical Research Communications·J D Veldhuis, E L Hewlett
Jun 1, 1987·Proceedings of the National Academy of Sciences of the United States of America·J S DavisL A West
Oct 1, 1993·Endocrine Reviews·J W Putney, G S Bird
Jun 1, 1993·Endocrine Reviews·D L Segaloff, M Ascoli
Jan 28, 1993·Nature·M J Berridge

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Citations

Nov 29, 2016·Frontiers in Physiology·Laurent MackayAnmar Khadra

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