The Vandenbergh effect is a phenomenon reported by J.G. Vandenbergh et al. in 1975, in which an early induction of the first estrous cycle in prepubertal female mice occurs as a result of exposure to the pheromone-laden urine of a sexually mature (dominant) male mouse.
Physiologically, the exposure to male urine induces the release of GnRH, which provokes the first estrus. The Vandenbergh effect has also been seen with exposure to adult female mice. When an immature female mouse is exposed to the urine of mature female mouse, estrus is delayed in the prepubertal female. In this situation, GnRH is inhibited and therefore delays puberty in the juvenile female mouse.[1]
The Vandenbergh effect is caused by pheromones found in a male’s urine. The male does not have to be present for this effect to take place; the urine alone is sufficient. These pheromones are detected by the vomeronasal organ in the septum of the female’s nose. This occurs because the female body will only take the step to begin puberty if there are available mates around. She will not waste energy on puberty if there is no possibility of finding a mate.[2]