April 2009
Volume 50, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2009
Growth Hormone Overexpression is Associated With Selective Inner Retina Dysfunction
Author Affiliations & Notes
  • B. T. Martin
    Physiology,
    University of Alberta, Edmonton, Alberta, Canada
  • E. O. List
    Edison Biotechnology Institute, Ohio University, Athens, Ohio
  • J. J. Kopchick
    Edison Biotechnology Institute, Ohio University, Athens, Ohio
  • Y. Sauvé
    Ophthalmology,
    University of Alberta, Edmonton, Alberta, Canada
  • S. Harvey
    Physiology,
    University of Alberta, Edmonton, Alberta, Canada
  • Footnotes
    Commercial Relationships  B.T. Martin, None; E.O. List, None; J.J. Kopchick, None; Y. Sauvé, None; S. Harvey, None.
  • Footnotes
    Support  Research supported by NSERC and CIHR, BTM supported by NSERC and AHFMR scholarships, JJK supported by the State of Ohio’s Eminent Scholars Program that includes a gift from Milton and Lawrence Goll.
Investigative Ophthalmology & Visual Science April 2009, Vol.50, 3606. doi:
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    • Get Citation

      B. T. Martin, E. O. List, J. J. Kopchick, Y. Sauvé, S. Harvey; Growth Hormone Overexpression is Associated With Selective Inner Retina Dysfunction. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3606.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: : The discovery of locally produced growth hormone (GH) and its receptor in the retina of rodents raises the possibility of functional GH effects on retina function. To test this hypothesis, we studied retina function in a mouse engineered to overexpress bovine GH (bGH).

Methods: : The electroretinogram (ERG) was recorded from 13 wild type (WT) and 11 bGH mice, at 2 months of age, after 2 hours of dark adaptation. A series of 19 flashes at increasing intensities (intensity response series from -5.22 to 2.86 log cd·s/m2) were presented to the anesthetised (xylazine-ketamine) mouse. Oscillatory potentials (OP1, OP2, OP3 and OP4) were isolated using a 75-300 Hz digital filter.

Results: : OP1 and OP2 amplitudes were selectively depressed in the bGH mouse, peaking at 69.4% and 69.8%, respectively, compared to WT. When values were normalized to the a-wave amplitude (to account for inter-animal variability in WT and bGH groups, respectively), OP1, OP2, and OP3 showed amplitude reductions (65%, 72%, 68%) in the bGH mouse compared to the WT. This was accompanied by a prolongation of the implicit time for the peak of OP2 (28.1 vs 31.1 ms, WT vs bGH) and OP3 (37.8 vs 41.6 ms), while the implicit time of a- and b-waves were unaffected. Fast-fourier transform analysis revealed that the OPs’ dominant frequency was significantly reduced in the bGH mice (100 Hz) compared to WT (108 Hz).

Keywords: retina: proximal (bipolar, amacrine, and ganglion cells) • electroretinography: non-clinical • transgenics/knock-outs 
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