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Background <p>Polycystic ovary syndrome (PCOS) is a complex endocrine-metabolic disorder characterised by hypothalamic-pituitary-gonadal (HPG) axis dysfunction and pathological gonadotropin-releasing hormone (GnRH) hypersecretion. While metformin demonstrates therapeutic efficacy in PCOS, its potential neuroendocrine mechanisms remain incompletely understood. This study aimed to investigate the involvement of hypothalamic signalling in metformin-responsive neuroendocrine regulation in PCOS.</p> Methods <p>Letrozole-induced PCOS rat models were treated with metformin to assess reproductive and metabolic outcomes. Data-independent acquisition (DIA) proteomics of hypothalamic tissue was performed to identify dysregulated pathways, followed by network analysis to explore candidate regulatory nodes. Mechanistic investigations were conducted in glucosamine-induced insulin-resistant GT1-7 GnRH neurons using pharmacological modulation and siRNA knockdown. In vivo functional relevance was examined using AAV-mediated Epac2 knockdown in the mouse arcuate nucleus.</p> Results <p>Metformin improved metabolic and reproductive abnormalities in PCOS rats, including insulin resistance, GnRH/LH hypersecretion, estrous cyclicity disruption, and ovarian morphological alterations. Hypothalamic proteomic and network analyses suggested that metformin-responsive changes were associated with insulin and cAMP-related signalling pathways. In GT1-7 neurons, metformin increased Epac2 expression, restored AKT signalling, and reduced GnRH overproduction under insulin-resistant conditions. Hypothalamic Epac2 knockdown reduced AKT signalling and was associated with systemic insulin resistance, increased GnRH/LH secretion, and preliminary supportive ovarian morphological observations, consistent with a functional contribution of Epac2 to reproductive-metabolic regulation.</p> Conclusions <p>These findings support the involvement of hypothalamic Epac2/AKT/GnRH signalling in metformin-responsive neuroendocrine regulation in PCOS. Further studies are required to determine the relative contributions of central and peripheral mechanisms.</p>

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Hypothalamic Epac2/AKT/GnRH signalling is associated with metformin-responsive neuroendocrine improvement in a PCOS model

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年7月24日

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  • Na Guo,
  • Hongyun Li,
  • Jinhong He,
  • Huanhuan Zhou,
  • Xing Wang,
  • Linlin Yang,
  • Huijuan Ma

摘要

Background

Polycystic ovary syndrome (PCOS) is a complex endocrine-metabolic disorder characterised by hypothalamic-pituitary-gonadal (HPG) axis dysfunction and pathological gonadotropin-releasing hormone (GnRH) hypersecretion. While metformin demonstrates therapeutic efficacy in PCOS, its potential neuroendocrine mechanisms remain incompletely understood. This study aimed to investigate the involvement of hypothalamic signalling in metformin-responsive neuroendocrine regulation in PCOS.

Methods

Letrozole-induced PCOS rat models were treated with metformin to assess reproductive and metabolic outcomes. Data-independent acquisition (DIA) proteomics of hypothalamic tissue was performed to identify dysregulated pathways, followed by network analysis to explore candidate regulatory nodes. Mechanistic investigations were conducted in glucosamine-induced insulin-resistant GT1-7 GnRH neurons using pharmacological modulation and siRNA knockdown. In vivo functional relevance was examined using AAV-mediated Epac2 knockdown in the mouse arcuate nucleus.

Results

Metformin improved metabolic and reproductive abnormalities in PCOS rats, including insulin resistance, GnRH/LH hypersecretion, estrous cyclicity disruption, and ovarian morphological alterations. Hypothalamic proteomic and network analyses suggested that metformin-responsive changes were associated with insulin and cAMP-related signalling pathways. In GT1-7 neurons, metformin increased Epac2 expression, restored AKT signalling, and reduced GnRH overproduction under insulin-resistant conditions. Hypothalamic Epac2 knockdown reduced AKT signalling and was associated with systemic insulin resistance, increased GnRH/LH secretion, and preliminary supportive ovarian morphological observations, consistent with a functional contribution of Epac2 to reproductive-metabolic regulation.

Conclusions

These findings support the involvement of hypothalamic Epac2/AKT/GnRH signalling in metformin-responsive neuroendocrine regulation in PCOS. Further studies are required to determine the relative contributions of central and peripheral mechanisms.