Sex-Dependent Effect of Metformin on Serum Prolactin Levels In Hyperprolactinemic Patients With Type 2 Diabetes: A Pilot Study

Exp Clin Endocrinol Diabetes. 2018 Jun;126(6):342-348. doi: 10.1055/s-0043-122224. Epub 2017 Nov 23.


Background: Metformin was found to reduce circulating levels of pituitary hormones.

Objective: The purpose of this study was to assess whether sex determines the effect of metformin on lactotroph secretory function.

Methods: The study population included 25 women and 12 men with mildly elevated serum prolactin levels (25-75 ng/mL). Because of concomitant type 2 diabetes, all participants were treated with metformin (3 g daily). Plasma levels of glucose and lipids, HOMA1-IR, serum levels of prolactin, thyrotropin and free thyroid hormones, as well as Jostel's, SPINA-GT and SPINA-GD indices were assessed at baseline and at the end of metformin treatment.

Results: The study completed 24 women and 11 men. At baseline, there were no significant differences in circulating levels of glucose and lipids, insulin sensitivity, hormones, Jostel's, SPINA-GT and SPINA-GD indices between women and men. In both men and women, metformin reduced fasting glucose levels and HOMA1-IR. However, only in women metformin decreased elevated prolactin levels and this effect correlated with an improvement insulin sensitivity, as well as with the impact on SPINA-GT.

Conclusions: The results of the study suggest that the effect of metformin on serum prolactin levels is sex-dependent.

Publication types

  • Clinical Trial

MeSH terms

  • Adolescent
  • Adult
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / complications
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Female
  • Humans
  • Hyperprolactinemia / blood
  • Hyperprolactinemia / complications
  • Hyperprolactinemia / drug therapy*
  • Lactotrophs / drug effects
  • Lactotrophs / metabolism
  • Male
  • Metformin / therapeutic use*
  • Middle Aged
  • Pilot Projects
  • Prolactin / blood*
  • Sex Characteristics
  • Treatment Outcome
  • Young Adult


  • Prolactin
  • Metformin