TY - JOUR
T1 - The effects of recombinant bovine somatotropin (rbST) on tissue IGF-I, IGF-I receptor, and GH mRNA levels in rainbow trout, Oncorhynchus mykiss
AU - Biga, Peggy R.
AU - Schelling, Gerald T.
AU - Hardy, Ronald W.
AU - Cain, Kenneth D.
AU - Overturf, Kenneth
AU - Ott, Troy L.
N1 - Funding Information:
The authors wish to thank Brian Peterson for his assistance in sample collection. This study was funded in part by NIH NCRR Grant P20-RR15587-01 to T.L.O. and USFWS No. 11982-1-G001095 to G.T.S.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2004/2
Y1 - 2004/2
N2 - Numerous studies demonstrated that rbST increased growth rates in several fish species, and several species exhibit GH production in tissues other than the pituitary. The role of tissue GH and IGF-I in regulating fish growth is poorly understood. Therefore an experiment was conducted to examine the effects of rbST treatment on tissue GH, IGF-I, and IGF-I receptor-A (rA) expression in rainbow trout. Rainbow trout (550±10g) received either intra-peritoneal injections of rbST (120μg/g body weight) or vehicle on days 0 and 21, and tissue samples were collected on days 0, 0.5, 1, 3, 7, and 28 (n=6/day/trt). Total RNA was isolated and assayed for steady-state levels of IGF-I, IGF-IrA, and GH mRNA using quantitative RT-PCR. Insulin-like growth factor-I mRNA levels increased in liver, gill, gonad, muscle, brain, and intestine in response to rbST treatment (P<0.10). Liver IGF-I mRNA increased (P<0.01) 0.5 day after treatment and remained elevated throughout the trial. Intestine IGF-I mRNA increased (P<0.05) in treated fish from day 1 to day 3, then decreased to day 7 and increased again at day 28, and remained elevated above control levels throughout the trial. Gill IGF-I mRNA levels increased (P<0.05) 1 day after treatment and remained elevated throughout the trial. Heart IGF-IrA mRNA levels decreased (P<0.05) while gonad GH mRNA levels increased (P<0.10) following rbST treatment. These results demonstrate that rbST treatment increased IGF-I mRNA levels in extra-hepatic tissues, and decreased heart IGF-IrA and increased gonad GH mRNA levels. Because the primary source for endocrine IGF-I is liver, the increased IGF-I mRNA reported in extra-hepatic tissues may indicate local paracrine/autocrine actions for IGF-I for local physiological functions.
AB - Numerous studies demonstrated that rbST increased growth rates in several fish species, and several species exhibit GH production in tissues other than the pituitary. The role of tissue GH and IGF-I in regulating fish growth is poorly understood. Therefore an experiment was conducted to examine the effects of rbST treatment on tissue GH, IGF-I, and IGF-I receptor-A (rA) expression in rainbow trout. Rainbow trout (550±10g) received either intra-peritoneal injections of rbST (120μg/g body weight) or vehicle on days 0 and 21, and tissue samples were collected on days 0, 0.5, 1, 3, 7, and 28 (n=6/day/trt). Total RNA was isolated and assayed for steady-state levels of IGF-I, IGF-IrA, and GH mRNA using quantitative RT-PCR. Insulin-like growth factor-I mRNA levels increased in liver, gill, gonad, muscle, brain, and intestine in response to rbST treatment (P<0.10). Liver IGF-I mRNA increased (P<0.01) 0.5 day after treatment and remained elevated throughout the trial. Intestine IGF-I mRNA increased (P<0.05) in treated fish from day 1 to day 3, then decreased to day 7 and increased again at day 28, and remained elevated above control levels throughout the trial. Gill IGF-I mRNA levels increased (P<0.05) 1 day after treatment and remained elevated throughout the trial. Heart IGF-IrA mRNA levels decreased (P<0.05) while gonad GH mRNA levels increased (P<0.10) following rbST treatment. These results demonstrate that rbST treatment increased IGF-I mRNA levels in extra-hepatic tissues, and decreased heart IGF-IrA and increased gonad GH mRNA levels. Because the primary source for endocrine IGF-I is liver, the increased IGF-I mRNA reported in extra-hepatic tissues may indicate local paracrine/autocrine actions for IGF-I for local physiological functions.
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U2 - 10.1016/j.ygcen.2003.10.014
DO - 10.1016/j.ygcen.2003.10.014
M3 - Article
C2 - 14723884
AN - SCOPUS:0346690140
SN - 0016-6480
VL - 135
SP - 324
EP - 333
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
IS - 3
ER -