GO066061 (National Center for Biotechnology Information 2010)] that had increased levels in treated tissue and showed slight homology to the growth hormone-releasing hormone receptor (GHRHR) gene (Fakhouri WD, Trail F, unpublished data).
We determined protein levels of GH, LH, PRL, and the GHRHR in the AtT-20 mouse pituitary tumor cell line [American Type Culture Collection (ATCC), Manassas, VA].
Rabbit anti-human GHRHR antibodies were purchased from Abeam (Cambridge, MA).
To determine whether ATR effects are mediated through the GHRHR, we used rat GHRF, a 43-amino acid peptide that binds specifically to GHRHR (Bloch et al.
Protein levels of GH, LH, PRL, and GHRHR in ATR-treated pituitary cell culture.
Previous studies on GHRHR binding have evaluated displacement of radiolabeled ligands at concentrations ranging from 30 to 80 [micro]g protein/mL (or 0.2 nM) by non-radiolabeled substances at concentrations ranging from [10.sup.-6] to [10.sup.-12] M (Rekasi et al.
To further test the role of ATR in affecting GH expression through GHRHR, we treated cells with ATR, Dex, or RU38486, alone or combined because Dex and RU38486 act as an agonist and an antagonist, respectively, to GH expression.
We included the histone H3 antibody as a nonspecific antibody to either ACTH receptor or GHRHR, which served as a negative control [see Supplemental Material, Figure 4 (doi:10.1289/ehp.0900738)].