Uncovering novel reproductive defects in neurokinin B receptor null mice: closing the gap between mice and men

Endocrinology. 2012 Mar;153(3):1498-508. doi: 10.1210/en.2011-1949. Epub 2012 Jan 17.


Patients bearing mutations in TAC3 and TACR3 (which encode neurokinin B and its receptor, respectively) have sexual infantilism and infertility due to GnRH deficiency. In contrast, Tacr3(-/-) mice have previously been reported to be fertile. Because of this apparent phenotypic discordance between mice and men bearing disabling mutations in Tacr3/TACR3, Tacr3 null mice were phenotyped with close attention to pubertal development, estrous cyclicity, and fertility. Tacr3(-/-) mice demonstrated normal timing of preputial separation and day of first estrus, markers of sexual maturation. However, at postnatal d 60, Tacr3(-/-) males had significantly smaller testes and lower FSH levels than their wild-type littermates. Tacr3(-/-) females had lower uterine weights and abnormal estrous cyclicity. Approximately half of Tacr3(-/-) females had no detectable corpora lutea on ovarian histology at postnatal d 60. Despite this apparent ovulatory defect, all Tacr3(-/-) females achieved fertility when mated. However, Tacr3(-/-) females were subfertile, having both reduced numbers of litters and pups per litter. The subfertility of these animals was not due to a primary ovarian defect, because they demonstrated a robust response to exogenous gonadotropins. Thus, although capable of fertility, Tacr3-deficient mice have central reproductive defects. The remarkable ability of acyclic female Tacr3 null mice to achieve fertility is reminiscent of the reversal of hypogonadotropic hypogonadism seen in a high proportion of human patients bearing mutations in TACR3. Tacr3 mice are a useful model to examine the mechanisms by which neurokinin B signaling modulates GnRH release.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Estrus / metabolism
  • Estrus / physiology
  • Female
  • Fertility
  • Gonadotropin-Releasing Hormone / metabolism
  • Heterozygote
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Models, Biological
  • Mutation
  • Neurons / metabolism
  • Phenotype
  • Receptors, Neurokinin-3 / genetics*
  • Reproduction
  • Testis / pathology
  • Time Factors


  • Receptors, Neurokinin-3
  • Gonadotropin-Releasing Hormone