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Insulin-like growth factor 1 regulates developing brain glucose metabolism
C M Cheng1, R R Reinhardt, W H Lee
1Developmental Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Summary
Brain insulin-like growth factor 1 (Igf1) is crucial for developing brain metabolism, promoting neuronal glucose uptake and growth. This study reveals Igf1
Area of Science:
- Neuroscience
- Developmental Biology
- Metabolic Research
Background:
- The developing brain has significant anabolic requirements.
- Insulin-like growth factor 1 (Igf1) is present in the brain.
- The precise role of endogenous brain Igf1 in early development is not fully understood.
Purpose of the Study:
- To investigate the role of endogenous brain insulin-like growth factor 1 (Igf1) in promoting neuronal glucose utilization and growth during early postnatal development.
- To elucidate the insulin-like functions of brain Igf1 in metabolic regulation.
Main Methods:
- Measurement of 2-deoxy-d-glucose uptake in wild-type and Igf1 knockout (Igf1-/-) mice.
- Analysis of glucose uptake in synaptosomes isolated from Igf1-/- brains.
- Assessment of Akt/PKB and GLUT4 phosphorylation and expression, as well as glycogen synthase kinase 3beta phosphorylation and glycogen accumulation in Igf1-/- neurons.
Main Results:
- Brain 2-deoxy-d-glucose uptake was reduced in Igf1-/- mice, particularly in brain regions with high Igf1 expression.
- Synaptosomal glucose uptake was diminished in Igf1-/- brains, with correction upon Igf1 addition.
- Igf1 deficiency led to reduced phosphorylation of Akt and GLUT4, and decreased phosphorylation of glycogen synthase kinase 3beta and glycogen accumulation in neurons.
Conclusions:
- Endogenous brain insulin-like growth factor 1 (Igf1) plays an essential, insulin-like role in supporting neuronal glucose utilization and growth during early brain development.
- Brain Igf1 is critical for anabolic processes in the developing brain, regulating glucose metabolism through pathways similar to peripheral insulin signaling.