The Joint Annual Scientific Meetings of the Endocrine Society of Australia and the Society for Reproductive Biology 2018

Accelerated ovarian reserve depletion has no effect on fertility in female Amh-/- mice. (#26)

Michael W Pankhurst 1
  1. Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand

The size of the ovarian reserve in each female is largely determined by events prior to puberty. However, the rate of ovarian reserve depletion is thought to influence fertility later in life. Depletion of the ovarian reserve by primordial follicle recruitment is modulated by multiple processes including anti-Müllerian hormone (AMH) signalling. AMH produced by granulosa cells inhibits primordial follicle activation, leading to an accelerated loss of ovarian reserve in AMH-/- mice. The assumed reduction of the fertility of female AMH-/- mice has not been tested. The aim of this experiment was to determine the age that reproductive output diverges in AMH+/+ and AMH-/- females and to examine the quality of AMH-/- mouse embryos at this phase of life. AMH+/+ males were paired with AMH-/- and AMH+/+ females and birth and litter size data were collected up until the age of 11 months. Unexpectedly, no differences were observed in litter size, parturition intervals or cumulative number of offspring at any age. Litter size declined in AMH+/+ and AMH-/- mice from around the 9th litter onwards. Few females remained fertile at 11 months of age but corpora lutea were present in the ovaries and cumulus-oocyte complexes were observed in the oviducts on the day of estrus in both strains, indicating ovulation was still occurring. This bears similarity to the age-related infertility that affects women approximately 10 years before menopause. The present data might indicate AMH has minor effects on ovarian reserve depletion, with little effect on fertility. Alternatively, the determinants of age-related infertility may be independent of the ovarian reserve. Ultimately, this study questions the current hypothesis that the role of AMH is to conserve the ovarian reserve to prolong the reproductive lifespan.