Effects of metformin on inappropriate LH release in women with polycystic ovarian syndrome and insulin resistance

Alfredo Ulloa-Aguirre, Lesly Portocarrero, Teresa Zariñán, Aleida Olivares, Sebastián Carranza-Lira, Johannes D. Veldhuis, Juan C. López-Alvarenga

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


The role of hyperinsulinaemia in neuroendocrine abnormalities in polycystic ovarian syndrome (PCOS) is controversial. The present study applied frequent blood sampling to assess the response of LH to metformin treatment in insulin-resistant women with PCOS. Thirteen predominantly overweight women with PCOS were studied before and after treatment with 1.5 g/day metformin for 3 months. Serum LH and testosterone were measured every 10 min for 10 h; LH was measured for an additional 2 h after gonadotrophin-releasing hormone (GnRH) administration. LH pulses were characterized by cluster analysis, secretory LH episodes by a deconvolution procedure, and synchronicity of paired LH-testosterone concentrations by lag-specific cross-correlation. After treatment, basal LH concentrations, amplitude of LH pulses, LH secretory amplitude, response to exogenous GnRH, and basal testosterone concentrations significantly decreased in seven patients, whereas in the remaining women these parameters remained unaltered. Before treatment, decreased coordinate LH and testosterone release was manifested by all patients; metformin treatment led to re-establishment of the feed-back control of testosterone on LH secretory rates by -20 to 0 min. Treatment did not modify the glucose:insulin ratio or serum insulin concentrations. In conclusion, administration of metformin allowed the identification of two subsets of PCOS women in whom neuroendocrine abnormalities may improve independently of the presence of insulin resistance or hyperinsulinaemia.

Original languageEnglish (US)
Article number2243
Pages (from-to)669-683
Number of pages15
JournalReproductive BioMedicine Online
Issue number6
StatePublished - Jun 2006


  • Insulin resistance
  • LH
  • Metformin
  • Polycystic ovarian syndrome
  • Testosterone

ASJC Scopus subject areas

  • Reproductive Medicine
  • Obstetrics and Gynecology
  • Developmental Biology


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