TY - JOUR
T1 - Divergent effects of insulin on insulin-like growth factor-II gene expression in the rat hypothalamus
AU - Lauterio, Thomas J.
AU - Aravich, Paul F.
AU - Rotwein, Peter
PY - 1990/1
Y1 - 1990/1
N2 - The effect of peripheral insulin treatment on brain content and synthesis of insulin-like growth factor-II (IGF-II) was studied in acute and chronic conditions. After a 3-h hyperinsulinemic/euglycemic clamp, rats were killed, and brains were removed for IGF-II analysis. Insulin infusion elevated IGF-II concentrations in the dorsomedial hypothalamus (DMH) and suprachiasmatic nucleus, but decreased IGF-II in the paraventricular nucleus, lateral hypothalamus (LtH), and supraoptic nucleus compared to values in control animals. In separate parallel studies, the effects of 4 days of insulin injection (1 U insulin/rat, sc, twice daily) on brain IGF-II mRNA and peptide were determined. For RNA analysis the hypothalamus was divided into three regions (lateral, ventral, and dorsal). IGF-II mRNA content was shown to vary by an order of magnitude within the adult rat hypothalamus under control conditions, and there appeared to be a differential region-dependent response to insulin treatment. Relative abundance of IGF-II mRNA in control hypothalami was VH ≫ cortex ≥ LtH > DMH. IGF-II mRNA content declined after insulin treatment in the VH, but rose in all other regions. Insulin increased IGF-II peptide content in the paraventricular nucleus, LtH, and VMH but decreased IGF-II in the DMH and suprachiasmatic nucleus. These results indicate that peripheral insulin status may be an important factor in the synthesis and secretion of IGF-II in the brain.
AB - The effect of peripheral insulin treatment on brain content and synthesis of insulin-like growth factor-II (IGF-II) was studied in acute and chronic conditions. After a 3-h hyperinsulinemic/euglycemic clamp, rats were killed, and brains were removed for IGF-II analysis. Insulin infusion elevated IGF-II concentrations in the dorsomedial hypothalamus (DMH) and suprachiasmatic nucleus, but decreased IGF-II in the paraventricular nucleus, lateral hypothalamus (LtH), and supraoptic nucleus compared to values in control animals. In separate parallel studies, the effects of 4 days of insulin injection (1 U insulin/rat, sc, twice daily) on brain IGF-II mRNA and peptide were determined. For RNA analysis the hypothalamus was divided into three regions (lateral, ventral, and dorsal). IGF-II mRNA content was shown to vary by an order of magnitude within the adult rat hypothalamus under control conditions, and there appeared to be a differential region-dependent response to insulin treatment. Relative abundance of IGF-II mRNA in control hypothalami was VH ≫ cortex ≥ LtH > DMH. IGF-II mRNA content declined after insulin treatment in the VH, but rose in all other regions. Insulin increased IGF-II peptide content in the paraventricular nucleus, LtH, and VMH but decreased IGF-II in the DMH and suprachiasmatic nucleus. These results indicate that peripheral insulin status may be an important factor in the synthesis and secretion of IGF-II in the brain.
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M3 - Article
C2 - 2403521
AN - SCOPUS:0025098322
SN - 0013-7227
VL - 126
SP - 392
EP - 398
JO - Endocrinology
JF - Endocrinology
IS - 1
ER -