Influence of nutritional status and oestradiol-17β on plasma growth hormone, insulin-like growth factors-I and -II and the response to exogenous growth hormone in young steers

• DOI: 10.1677/joe.0.1180243
• Publication Date: 2008-12-11T22:52:58Z
• Authors: B. H. Breier; P. D. Gluckman; J. J. Bass
• Keywords: Basal (medicine); Bolus (digestion); Somatomedin

ABSTRACT Plasma GH profiles and circulating concentrations of plasma insulin-like growth factors-I -II (IGF-I -II) were examined in 20 steers on either high (3% dry matter body weight per day) or low (1% planes nutrition with without an implant oestradiol-17β. The response IGF-I to a bolus injection bovine (bGH) was also investigated. Reduced feeding significantly ( P <0·01) increased the mean concentration, peak height integrated area GH. Treatment oestradiol at baseline concentrations. <0·05) mean, baseline, height, pulse frequency not changed by nutritional plane treatment. Basal decreased reduced both oestradiol-treated control group. basal levels nutrition. After i.v. bGH (0·1 mg/kg weight), increase observed only IGF-II altered manipulations but <0·001) infusion showed IGF-II. Significant correlations between daily gain r = 0·91, <0·001, n 20) capacity high-affinity hepatic somatotrophic receptor 0·89, n= 10). Decreased level may abolish growth-promoting activity secretion number receptors treatment represent coordinated axis leading enhanced production improved rate. inferential relationships receptor, rates suggest that active modulation is important regulatory constituent axis. J. Endocr . (1988) 118, 243–250