Adrenalectomy (ADX) Reduces the Orexigenic Response to Ghrelin

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 542-571-Energy Balance: Control of Adiposity and Feeding
Basic
Saturday, March 7, 2015: 1:00 PM-3:00 PM
Hall D-F, Obesity (San Diego Convention Center)

Poster Board SAT-550
Matheus Porceban1, Jose Antunes-Rodrigues, MD, PhD2 and Lucila Elias, MD, PhD2
1University of São Paulo, 2Ribeirao Preto Medical School - University of Sao Paulo, Ribeirao Preto, Brazil
It is known that ADX leads to reduced body weight and hypophagia, however, there are no data on interaction of glucocorticoids and ghrelin, hormone synthesized in the stomach, with orexigenic action. Thus, we evaluated in this study the response to ghrelin stimulus in adrenalectomized rats with or without corticosterone replacement. Adult male Wistar rats (Ethical Committee on Animal Experiments of Ribeirão Preto Medical School, Nº 104/2012, 7 to 10 animals per group) were subdivided into ADX (0.5% ethanol in 0.9% NaCl), ADX+B (25 mg/L of corticosterone in 0.5% ethanol and 0.9% NaCl) or Sham (0.5% ethanol  in water) groups and treated for 7 days. The animals were acclimatized in metabolic cages and on 7th day, the food was removed at 4h30pm and 1 hour later the rats were treated with ip injection of vehicle (0.9% NaCl) or ghrelin (39µg/Kg). The food intake was measured 1 hour after the injection. Another group of animals, 7 days after surgery, was decapitated at 5:30pm for blood sample collection for measurement of serum concentration of acylated ghrelin, by ELISA. The stimulus with ghrelin increased (p<0.05) food intake in the three groups (saline vs ghrelin: Sham: 0.97 ± 0.1 g/100g vs 1.6 ± 0.1 g/100g of body weight; ADX: 0.5 ± 0.1 vs 1.0 ± 0 of body weight; ADX+B: 1.0 ± 0.1 g/100g vs 1.5 ± 0.2 g/100g of body weight). Though the ADX group showed the orexigenic effect of ghrelin, it was lower than in Sham and ADX+B groups, since the anorexigenic effect of ADX was maintained after ghrelin treatment. There was no difference in the serum concentration of ghrelin among the three groups (Sham: 107.6 ± 1.9; ADX: 107.9 ± 1.0; ADX+B: 106 ± 0.9 pg/ml).  In conclusion, glucocorticoid deficiency induced by ADX does not affect the production of acylated ghrelin. Although ghrelin is able to induce food intake after ADX, this effect is attenuated by the absence of endogenous glucocorticoids. These data indicate that hypophagia in primary adrenal insufficiency is associated with lower appetitive ingestive behavior, at least in part, due to lower ghrelin action on  food intake, which seems to be modulated by glucocorticoids.

Nothing to Disclose: MP, JA, LE

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Sources of Research Support: Sao Paulo Research Foundation (FAPESP)