Meeting Abstract

87.4  Thursday, Jan. 7  Endocrine control of growth in coho salmon: validation of a multiplex gene expression assay and quantification of relations between messenger RNA levels and proteins during feeding and fasting BECKMAN, Brian R*; LUCKENBACH, J Adam; METZGER, David C; SHIMIZU, Munetaka; DICKEY, Jon T; NWFSC, NOAA Fisheries; NWFSC, NOAA Fisheries; NWFSC, NOAA Fisheries; School of Fisheries, University of Hokkaido; SAFS, University of Washington brian.beckman@noaa.gov

We have explored the efficacy of the recently-released Quantigene Plex (QGP) technology for measuring a panel of endocrine growth-related transcripts in the liver of coho salmon, Oncorhynchus kisutch. The QGP technology uses sequence specific probes and requires no reverse transcription or amplification as does real-time, quantitative RT-PCR (qRT-PCR). Using liver homogenates from fed, fasted and re-fed coho salmon, we compared the detectable fold changes of steady-state mRNA levels between the QGP and probe based qRT-PCR assays for insulin-like growth factors (igf1 and igf2), insulin-like growth factor binding proteins (igfbp1, igfbp2a, and igfbp2b), somatolactin receptor (slr), and growth hormone receptors (ghr1 and ghr2). A positive and significant relation between QGP and qRT-PCR results was found for each gene target, demonstrating that the QGP assay is a valid approach for assessing gene expression of each of these genes. Messenger RNA levels of igf1, igf2, igfbp2a, and slr decreased with fasting, levels of igfbp1, ghr1 and ghr2 increased with fasting, and there was little change in levels of igfbp2b. Positive and significant correlations were found between igf1 and igf2 mRNA levels, igfbp2a and igfbp2b; igf2 and igfbp2a; igfbp2a and igfbp2b; and ghr1 and ghr2. Finally, positive and significant relations were found between liver igf1 mRNA and plasma IGF1 and liver igfbp1 mRNA and plasma IGFBP1.