Acute effects of metformin therapy include improvement of insulin resistance and ovarian morphology

Longitudinal assessment of antimüllerian hormone during pregnancy—relationship with maternal adiposity, insulin, and adiponectin

“…If the former is correct, this would suggest that the observed elevation in AMH in women with hyperinsulinemia and PCOS (8) is indirect, reflecting the presence of increased preantral follicular development, whose origin is related only partly to insulin metabolism. Consistent with a lack of a direct effect of insulin, we did not see a relationship with the insulin resistance marker SHBG, and short-term use of metformin is known not to alter AMH despite improvements in insulin sensitivity (9). In contrast, long-term metformin use induces marginal decreases in weight and AMH, consistent with the relationships to adiposity (10) seen in this cohort analysis.…”

The Use of Anti-Müllerian Hormone in Predicting Menstrual Response after Weight Loss in Overweight Women with Polycystic Ovary Syndrome

“…Furthermore, AMH levels are higher in amenorrheic women with PCOS compared with oligomenorrhea women with PCOS in conjunction with significantly elevated 2-to 9-mm follicle number per ovary, and AMH has been proposed as a surrogate marker for antral follicle count in PCOS (21). Although a number of studies have demonstrated improvements in menstrual function and reductions in AMH after metformin therapy in women with PCOS (20,22,23), the relationship of AMH to menstrual improvements after weight loss is unknown. Therefore, the aim of this study was to test the hypothesis that elevated preweight loss AMH levels are higher in women with PCOS who do not respond to weight loss with menstrual improvements compared with women with PCOS who display menstrual improvements after weight loss.…”

“…Women with PCOS and higher surrogate measures of insulin resistance had similar levels of AMH compared with those with lower surrogate measures of insulin resistance (20), and no association (22) or a positive correlation (43) was reported between insulin and AMH. Furthermore, although short-term metformin administration (1 wk to 4 months) resulted in improvements in hyperandrogenism, menstrual cyclicity (22), surrogate measures of insulin sensitivity, and reductions in antral follicle number (20), long-term metformin administration (6 -8 months) was required for reductions in AMH (22,23). Therefore, menstrual improvements after weight loss may be due to reductions in factors, including insulin-stimulated androgen production, although it has not yet been examined if these are related to changes in AMH.…”

Anti-Müllerian hormone and polycystic ovary syndrome: a mountain too high?

“…Insulin has been shown to enhance gonadotrophin-stimulated steroid production in GCs and theca (Willis et al 1996); therefore, the raised AMH concentrations may be secondary to an effect of insulin on androgen levels. Although this is a possible cause, other studies have failed to find a direct correlation between insulin and AMH concentrations (Pigny et al 2003, Eldar-Geva et al 2005, and even when insulin levels have reduced with treatment, a fall in serum AMH has not followed directly (Bayrak et al 2007, Carlsen et al 2009). It is possible that there is an intrinsic over-expression of the AMH gene causing the raised production of the protein in the PCO or that the currently unknown factor driving the androgen production also increases AMH.…”

“…Certainly over the course of a single week, metformin did not reduce the serum AMH level despite there being a reduction in antral follicle number (Bayrak et al 2007). This is not surprising given that in other studies it was not until after 4, 6 or 8 months of metformin treatment that AMH levels fell (Fleming et al 2005).…”