Association of Early Pubertal Onset in Female Rats with Inhalation of Lavender Oil

Abstract

Background Central precocious puberty is caused by early activation of the hypothalamic–pituitary–gonadal axis but its major cause remains unclear. Studies have indicated an association between chronic environmental exposure to endocrine-disrupting chemicals and pubertal onset. Methods To evaluate this association, we compared the hormone levels and timing of vaginal opening in female rats exposed to lavender oil (LO) through different routes [study groups: control, LO nasal spray (LS), and indoor exposure to LO (LE)] during the prepubertal period. The body weights of the animals were also compared every 3 days until the day of vaginal opening, at which time gonadotropin levels and internal organ weights were assessed. Results The LS group showed early vaginal opening at 33.8 ± 1.8 days compared with the control (38.4 ± 2.9 days) and LE (36.6 ± 1.5 days) groups. Additionally, luteinizing hormone levels were significantly higher in the LE and LS groups than in the control group. Body weights did not differ significantly among the groups. Conclusions Exposure to an exogenic simulant via inhalation during the prepubertal period triggered early puberty onset in female rats. Further evaluation of exposure to other endocrine-disrupting chemicals capable of inducing central precocious puberty through the skin, orally, and/or nasally is warranted.