Effects of short-term growth hormone treatment on liver and muscle transcriptomes in rainbow trout (Oncorhynchus mykiss).
Although studies have established that exogenous growth hormone (GH) treatment stimulates growth in fish, its effects on target tissue gene expression are not well characterized. We assessed the effects of Posilac (Monsanto, St. Louis, MO), a recombinant bovine GH, on tissue transcript levels in rainbow trout selected from two high-growth rate and two low-growth rate families. Transcript abundance was measured in liver and muscle with the Genome Research in Atlantic Salmon Project (GRASP) 16K cDNA microarray. A selection of the genes identified as altered by the microarray and transcripts for insulin-like growth factors, growth hormone receptors (GHRs), and myostatins were measured by real-time PCR in the liver, muscle, brain, kidney, intestine, stomach, gill, and heart. In general, transcripts identified as differentially regulated in the muscle on the microarray showed similar directional changes of expression in the other nonhepatic tissues. A total of 114 and 66 transcripts were identified by microarray as differentially expressed with GH treatment across growth rate for muscle and liver, respectively. The largest proportion of these transcripts represented novel transcripts, followed by immune and metabolism-related genes. We have identified a number of genes related to lipid metabolism, supporting a modulation in lipid metabolism following GH treatment. Most notable among the growth-axis genes measured by real-time PCR were increases in GHR1 and -2 transcripts in liver and muscle. Our results indicate that short-term GH treatment activates the immune system, shifts the metabolic sectors, and modulates growth-regulating genes.
Gahr
Scott A
SA
National Center for Cool and Cold Water Aquaculture, Agriculture Research Service, United States Department of Agriculture, Kearneysville, West Virginia 25430, USA. scott.gahr@ars.usda.gov
Vallejo
Roger L
RL
Weber
Gregory M
GM
Shepherd
Brian S
BS
Silverstein
Jeffrey T
JT
Rexroad
Caird E
CE
D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D003692:Delayed-Action Preparations; D004064:Digestive System / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D005880:Gills / Q000378:metabolism; D013006:Growth Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D017686:Oncorhynchus mykiss / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D009928:Organ Specificity; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects*
D003692:Delayed-Action Preparations; D012333:RNA, Messenger; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone