Abstract:

Objective To investigate the impacts of hormone inhibition during minipuberty on adolescent gonadal axis function of male rats. Methods ①The concentrations of serum testosterone (T), luteotropic hormone (LH), follicle-stimulating hormone (FSH) and testicular weight of normal male rats were measured at different time points after birth (0, 2, 4, 6, and 24 h) to confirm the existence of minipuberty. ②“No minipuberty” models were established by using ether inhalation to male neonatal rats in 5 min after birth. ③Bilateral testes and epididymis weight and testicular pathologic changes were compared between the model and control group at the age of 45 d and 75 d. Serum T levels were tested by ELISA. And expressions of testicular androgen receptor (AR) mRNA, insulin-like growth factor 3 (INSL3) mRNA, anti-mullerian homone (AMH) mRNA, and Ghrelin mRNA were determined by real-time PCR assay. Results ①In the neonatal male rats, serum T and LH levels reached a maximum at 2 h after birth. FSH level rose to peak in 30 min, and bilateral testicular weight also reached a short-term peak at 4 h. ②In model group, serum T, LH, and FSH levels showed remarkable descent, which was proved establishment of “no minipuberty” model. ③Impaired evidences were found in testicular pathologic images of model group at the age of 45 d. Ghrelin gene mRNA expression at 45d of age and AR gene mRNA expression at 75 d of age had no statistical difference between the two group, but there was an obvious decrease tendency in model group (P=0.055, P=0.050). AMH mRNA expression in model group was significantly lower than that in the control group at 75 d of age (P=0.024). Conclusion Minipuberty was confirmed to exist in male rats which lasted about 6 h. Inhibition of minipuberty by ether inhalation was proved to have long-term effect on gonadal function of male rats.

Key words: minipuberty, male rat, sex development