Alteration of ghrelin-neuropeptide Y network in obese patients with polycystic ovary syndrome: Role of hyperinsulinism

Daniela Romualdi, Laura De Marinis, Giuseppe Campagna, Caterina Proto, Antonio Lanzone, Maurizio Guido

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: Insulin, ghrelin, neuropeptide Y (NPY) and leptin interact in the regulation of energy homeostasis. Most of these signals are altered in polycystic ovary syndrome (PCOS), which is characterized by a high prevalence of obesity. The present study was conducted to evaluate ghrelin-NPY and ghrelin-leptin interplays in relation to insulin secretion in obese PCOS subjects. Design: Pilot prospective study. Patients: Seven obese PCOS women and seven age-weight matched controls. Measurements: Hormonal measurements, oral glucose tolerance test (OGTT) and a ghrelin test (1 μg/kg i.v. bolus). PCOS patients repeated the clinical work-up after 4 months of metformin treatment (1500 mg/day orally). Results: At baseline, PCOS women showed a significantly higher insulinaemic response to the OGTT compared to controls (P <0.05). In basal conditions, PCOS women exhibited lower NPY levels than controls (P <0.01). Ghrelin injection markedly increased NPY in controls (P <0.01), whereas PCOS women showed a deeply blunted NPY response to the stimulus (area under the curve - AUC-NPY: P <0.01 vs. controls.). Metformin treatment induced a significant decrease in insulin levels (P <0.01) and the concomitant recovery of NPY secretory capacity in response to ghrelin (AUC-NPY: P <0.05 vs. baseline) in PCOS women. Leptin levels, which were similar in the two groups, were not modified by ghrelin injection; metformin did not affect this pattern. Conclusion: Hyperinsulinaemia seems to play a pivotal role in the alteration of NPY response to ghrelin in obese PCOS women. This derangement could be implicated in the physiopatology of obesity in these patients.

Original languageEnglish
Pages (from-to)562-567
Number of pages6
JournalClinical Endocrinology
Volume69
Issue number4
DOIs
Publication statusPublished - Oct 2008

ASJC Scopus subject areas

  • Endocrinology

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