TY - JOUR
T1 - Suppression of insulin-like growth factor I during epidermal growth factor-induced growth retardation
AU - Chernausek, S. D.
AU - Dickson, B. A.
AU - Smith, E. P.
AU - Hoath, S. B.
PY - 1991
Y1 - 1991
N2 - Epidermal growth factor (EGF) attenuates growth when administered to rats <2 wk of age but lacks growth-retarding properties when given to older animals. Because the insulin-like growth factors (IGF) are postulated to be important regulators of somatic growth during the perinatal period, we examined the effect of exogenous EGF on serum and tissue concentrations of IGF-I and hepatic expression of mRNA for IGF-I and IGF-II. A single injection of EGF (500 ng/g body wt) produced a significant (P < 0.01) decline in serum IGF-I concentration within 4 h in newborn rat pups [controls, 46.2 ± 9.1 (SD) ng/ml; EGF treated, 29.4 ± 4.0 ng/ml] but was ineffective in 2-wk-old animals (control IGF-I, 72.8 ± 15.1 vs. 64.0 ± 13.7 ng/ml). When the EGF was given on days 0-3 of life, circulating IGF-I concentrations were suppressed further (control, 61.4 ± 8.6; EGF treated, 32.5 ± 8.6 ng/ml). Despite the change in circulating IGF-I levels in the newborn rats, the amount of IGF-I extractable from liver and kidney of growth-retarded animals was not significantly different from control. Likewise, IGF-I and IGF-II mRNA expression in liver, as assessed by blot hybridization, was unchanged by the EGF treatment. The rapid decline in IGF-I concentration after EGF administration, coupled with the restriction of this phenomenon the first 2 wk of extrauterine life, implies that changes in IGF-I are involved in the pathogenesis of EGF-induced growth retardation.
AB - Epidermal growth factor (EGF) attenuates growth when administered to rats <2 wk of age but lacks growth-retarding properties when given to older animals. Because the insulin-like growth factors (IGF) are postulated to be important regulators of somatic growth during the perinatal period, we examined the effect of exogenous EGF on serum and tissue concentrations of IGF-I and hepatic expression of mRNA for IGF-I and IGF-II. A single injection of EGF (500 ng/g body wt) produced a significant (P < 0.01) decline in serum IGF-I concentration within 4 h in newborn rat pups [controls, 46.2 ± 9.1 (SD) ng/ml; EGF treated, 29.4 ± 4.0 ng/ml] but was ineffective in 2-wk-old animals (control IGF-I, 72.8 ± 15.1 vs. 64.0 ± 13.7 ng/ml). When the EGF was given on days 0-3 of life, circulating IGF-I concentrations were suppressed further (control, 61.4 ± 8.6; EGF treated, 32.5 ± 8.6 ng/ml). Despite the change in circulating IGF-I levels in the newborn rats, the amount of IGF-I extractable from liver and kidney of growth-retarded animals was not significantly different from control. Likewise, IGF-I and IGF-II mRNA expression in liver, as assessed by blot hybridization, was unchanged by the EGF treatment. The rapid decline in IGF-I concentration after EGF administration, coupled with the restriction of this phenomenon the first 2 wk of extrauterine life, implies that changes in IGF-I are involved in the pathogenesis of EGF-induced growth retardation.
KW - Perinatal growth
KW - Rat
KW - Somatomedins
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U2 - 10.1152/ajpendo.1991.260.3.e416
DO - 10.1152/ajpendo.1991.260.3.e416
M3 - Article
C2 - 2003595
AN - SCOPUS:0025731249
SN - 0002-9513
VL - 260
SP - E416-E421
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 3 23-3
ER -