Alicia White, Jane Stremming, Stephanie R Wesolowski, Saif I Al-Juboori, Evgenia Dobrinskikh, Sean W Limesand, Laura D Brown, Paul J Rozance
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引用次数: 0
Abstract
Insulin-like growth factor-1 (IGF-1) and insulin are important fetal anabolic hormones. Complications of pregnancy, such as placental insufficiency, can lead to fetal growth restriction FGR) with low circulating IGF-1 and insulin concentrations and attenuated glucose-stimulated insulin secretion (GSIS), which likely contribute to neonatal glucose dysregulation. We previously demonstrated that a one-week infusion of IGF-1 LR3, an IGF-1 analog with low affinity for IGF binding proteins and high affinity for the IGF-1 receptor, at 6.6 μg·kg-1·hr-1 into normal fetal sheep increased body weight but lowered insulin concentrations and GSIS. In this study, FGR fetal sheep received either IGF-1 LR3 treatment at 1.17 ± 0.12 μg·kg-1·hr-1 (LR3; n=7) or vehicle (VEH; n=7) for one week. Plasma insulin, glucose, oxygen, and amino acids were measured before starting treatment and at the end of the treatment period. GSIS was measured on the final treatment day. Fetal body weights, insulin, glucose, oxygen, and GSIS were not different between groups. Amino acid concentrations decreased in LR3 (Baseline vs Final individual means comparison P=0.0232) but not in VEH (P=0.3866). In summary, a one-week IGF-1 LR3 treatment did not improve growth in FGR fetuses. Insulin concentrations and GSIS were not attenuated by IGF-1 LR3, yet circulating amino acids decreased, which could reflect increased amino acid utilization. We speculate that maintaining amino acid concentrations or raising insulin, glucose, and/or oxygen concentrations to values consistent with normally growing fetuses during IGF-1 LR3 treatment may be necessary to increase fetal growth in the setting of placental insufficiency and FGR.
期刊介绍:
The American Journal of Physiology-Endocrinology and Metabolism publishes original, mechanistic studies on the physiology of endocrine and metabolic systems. Physiological, cellular, and molecular studies in whole animals or humans will be considered. Specific themes include, but are not limited to, mechanisms of hormone and growth factor action; hormonal and nutritional regulation of metabolism, inflammation, microbiome and energy balance; integrative organ cross talk; paracrine and autocrine control of endocrine cells; function and activation of hormone receptors; endocrine or metabolic control of channels, transporters, and membrane function; temporal analysis of hormone secretion and metabolism; and mathematical/kinetic modeling of metabolism. Novel molecular, immunological, or biophysical studies of hormone action are also welcome.