The effect of insulin-induced hypoglycemia on gene expression in the hypothalamic-pituitary-adrenal axis of the rat
| Autor: | K Mealy, B. G. Robinson, Joseph A. Majzoub, D W Wilmore |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Blood Glucose
Male Hypothalamo-Hypophyseal System medicine.medical_specialty Vasopressin Pro-Opiomelanocortin Corticotropin-Releasing Hormone medicine.medical_treatment Gene Expression Pituitary-Adrenal System Neuropeptide Biology Hypoglycemia chemistry.chemical_compound Endocrinology Adrenocorticotropic Hormone Anterior pituitary Corticosterone Internal medicine medicine Animals Insulin RNA Messenger Pancreatic hormone Rats Inbred Strains Blotting Northern medicine.disease Rats Arginine Vasopressin medicine.anatomical_structure chemistry hormones hormone substitutes and hormone antagonists Hypothalamic–pituitary–adrenal axis |
| Zdroj: | Endocrinology. 130:920-925 |
| ISSN: | 1945-7170 0013-7227 |
| DOI: | 10.1210/endo.130.2.1310284 |
| Popis: | This study has examined the effects of insulin-induced hypoglycemia on expression of the CRH, arginine vasopressin, and POMC genes and corresponding peptides in freely moving, unanesthetized, male Sprague-Dawley rats. Animals were infused with 150 mM NaCl for 3 days before the experimental day and were then administered insulin (4 U/kg) or saline iv. In one experiment animals were killed 0, 30, 60, or 90 min after insulin or saline, and RNA was isolated from anterior pituitary, cerebral cortex, and punches of the hypothalamic paraventricular and supraoptic nuclei. In a second experiment, animals were killed 90 min after insulin or saline treatment, and RNA was isolated from whole hypothalami. RNA was analyzed by Northern blot. Plasma glucose fell from 106 +/- 5 to 38 +/- 2 mg/dl after insulin administration and remained low for the duration of the experiment. Plasma levels of ACTH, corticosterone, and vasopressin were 10-, 6-, and 4-fold higher, respectively, in the insulin-treated vs. control animals (by analysis of variance, P less than 0.0001 in all cases), while plasma CRH was unchanged. During hypoglycemia POMC mRNA levels were 1.8-fold higher in the insulin-treated group (by analysis of variance, P less than 0.025). In contrast, paraventricular nucleus, whole hypothalamic, and parietal cortex CRH mRNA and vasopressin mRNA were unchanged. These data support previous studies which indicated that POMC gene expression is increased by hypoglycemia. However, we found no evidence for an increase in paraventricular nucleus or cerebral cortex CRH mRNA expression during hypoglycemia-associated stimulation of the hypothalamic-pituitary-adrenal axis, suggesting that another factor(s) may mediate the observed increase in POMC gene expression. |
| Databáze: | OpenAIRE |
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