Robyn Tamboli
Last active: 1/23/2018

Metabolic responses to exogenous ghrelin in obesity and early after Roux-en-Y gastric bypass in humans.

Tamboli RA, Antoun J, Sidani RM, Clements A, Harmata EE, Marks-Shulman P, Gaylinn BD, Williams B, Clements RH, Albaugh VL, Abumrad NN
Diabetes Obes Metab. 2017 19 (9): 1267-1275

PMID: 28345790 · PMCID: PMC5568950 · DOI:10.1111/dom.12952

AIMS - Ghrelin is a gastric-derived hormone that stimulates growth hormone (GH) secretion and has a multi-faceted role in the regulation of energy homeostasis, including glucose metabolism. Circulating ghrelin concentrations are modulated in response to nutritional status, but responses to ghrelin in altered metabolic states are poorly understood. We investigated the metabolic effects of ghrelin in obesity and early after Roux-en-Y gastric bypass (RYGB).

MATERIALS AND METHODS - We assessed central and peripheral metabolic responses to acyl ghrelin infusion (1 pmol kg  min ) in healthy, lean subjects (n = 9) and non-diabetic, obese subjects (n = 9) before and 2 weeks after RYGB. Central responses were assessed by GH and pancreatic polypeptide (surrogate for vagal activity) secretion. Peripheral responses were assessed by hepatic and skeletal muscle insulin sensitivity during a hyperinsulinaemic-euglycaemic clamp.

RESULTS - Ghrelin-stimulated GH secretion was attenuated in obese subjects, but was restored by RYGB to a response similar to that of lean subjects. The heightened pancreatic polypeptide response to ghrelin infusion in the obese was attenuated after RYGB. Hepatic glucose production and hepatic insulin sensitivity were not altered by ghrelin infusion in RYGB subjects. Skeletal muscle insulin sensitivity was impaired to a similar degree in lean, obese and post-RYGB individuals in response to ghrelin infusion.

CONCLUSIONS - These data suggest that obesity is characterized by abnormal central, but not peripheral, responsiveness to ghrelin that can be restored early after RYGB before significant weight loss. Further work is necessary to fully elucidate the role of ghrelin in the metabolic changes that occur in obesity and following RYGB.

© 2017 John Wiley & Sons Ltd.

MeSH Terms (24)

Acylation Anti-Obesity Agents Cohort Studies Combined Modality Therapy Cross-Over Studies Energy Metabolism Gastric Bypass Ghrelin Gluconeogenesis Glucose Clamp Technique Human Growth Hormone Humans Infusions, Intravenous Insulin Resistance Liver Muscle, Skeletal Obesity, Morbid Pancreatic Polypeptide Pancreatic Polypeptide-Secreting Cells Pituitary Gland, Anterior Postoperative Care Preoperative Care Protein Precursors Single-Blind Method

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