Abstract

In rats and humans estradiol attenuates neuroendocrine responses to hypoglycemia. Since neuroendocrine responses to hypoglycemia are mediated by hypothalamic neurons, we assessed if estradiol attenuates hypoglycemia-induced gene expression in the hypothalamus in female ovariectomized mice. As expected, estradiol-implanted ovariectomized mice exhibited increased plasma estradiol, increased uterine weight, decreased body weight, decreased visceral adiposity, and enhanced glucose tolerance with decreased plasma insulin. Estradiol-implanted mice exhibited attenuated hypoglycemia-induced gene expression of both glucose transporter 1 (Glut1) and inhibitor of kappa beta signaling (IκB) in the hypothalamus but not in the liver. Estradiol also attenuated hypoglycemia-induced plasma glucagon, pituitary proopiomelanocortin (POMC), and adrenal c-fos, consistent with impaired counterregulatory responses to hypoglycemia. In addition, estradiol inhibited hypothalamic expression of carnitine palmitoyltransferase (CPT1a and CPT1c) and pyruvate dehydrogenase kinase 4 (PDK4), effects that would be expected to enhance the accumulation of long-chain fatty acids and glycolysis. Taken together, these findings suggest hypothalamic mechanisms mediating attenuation of hypoglycemia-induced neuroendocrine responses.

Original languageEnglish
Pages (from-to)77-83
Number of pages7
JournalBrain Research
Volume1280
DOIs
StatePublished - 14 Jul 2009

Keywords

  • Estradiol
  • Gene expression
  • Hypoglycemia
  • Hypothalamus

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