Influence of the male on provoked ovulation in immature female mice.

Acceleration of ovulation in juvenile females by exposure to the male and injection of gonadotrophins was investigated. The male-induced ovulation in CBA/kw and outbred females was observed only after injection of PMSG. Exposure to the male and injection of HCG did not evoke this effect. Our results indicated that the presence of a male stimulates LH release from the pituitary of juvenile females. Pheromonal reaction of the females was affected by the age and body weight of the tested animals. Most sensitive were females of CBA/kw strain 21-day-old, outbred 21-day-old, 10.0-12.0 g and 24-day-old, 7.5-9.5 g.