Hormonally-regulated expression of voltage-operated Ca²⁺ channels in osteocytic (MLO-Y4) cells

Yuchun Gu, MR Preston, J Magnay, AJ El Haj, Stephen Publicover

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37 Citations (Scopus)


Voltage operated calcium channels (VOCCs) are important in stimulus-response coupling in osteoblasts. We have investigated the expression of VOCCs in the mouse osteocyte cell line, MLO-Y4. Using the whole-cell patch clamp technique we were unable to detect any VOCC currents (n = 436) even in the presence of the L-type VOCC agonist Bay K 8644 (n = 350). Reverse transcription polymerase chain reaction (RT-PCR), using primers to detect alpha(1C), alpha(1D), and alpha(1G) VOCC subunits (all of which are expressed in primary osteoblasts), did not generate detectable products with mRNA from MLO-Y4 cells. However, after treatment with physiological levels of hormones, VOCC alpha(1) subunit mRNAs were detected in MLO-Y4 cells. PTH, 17beta-estradiol, and dexamethasone-treatment induced expression of L-type (alpha(1C), alpha(1D)) subunit transcripts. ATP-treatment induced expression of T-type (alpha(1G)) transcripts. Using whole-cell patch clamp we detected VOCC currents in 5-10% of cells after treatment. Current characteristics (L- or T-type) were consistent with the transcript expressed.
Original languageEnglish
Pages (from-to)536-542
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number2
Publication statusPublished - 30 Mar 2001


  • oestradiol
  • bone
  • PTH
  • deamethasone
  • ATP
  • osteocyte
  • MLO-Y4
  • voltage-operated Ca2+ channel


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