Inhibition of sexual maturation in juvenile female and male mice by a chemosignal of female origin.

Maturation of juvenile house mice (Mus domesticus) exposed to synthetic 2,5-dimethylpyrazine was compared to the maturation of juvenile male and female mice exposed to urine from adult males and grouped females. Exposure of juvenile male mice to the synthetic compound significantly inhibited the growth of their testes and sex-accessory glands in a fashion similar to the urine of adult males and grouped females. The uterine weight and the presence of ova in the oviducts in females was strongly affected by synthetic stimuli. The majority of females (76-84%) exposed either to grouped females' urine or to the synthetic compound did not exhibit significant uterine weight increase and did not achieve pubertal ovulation before the age of 30 days as it has been reported for control mice. It is suggested that 2,5-dimethylpyrazine delays puberty of juvenile conspecifics in a population and may function whenever the living conditions of growing animals are below the level required for successful reproduction.